Base class for matrices, part 0

Note

For design documentation see matrix/docs.py.

EXAMPLES:

sage: matrix(2, [1,2,3,4])
[1 2]
[3 4]

>>> from sage.all import *
>>> matrix(Integer(2), [Integer(1),Integer(2),Integer(3),Integer(4)])
[1 2]
[3 4]

matrix(2, [1,2,3,4])
class sage.matrix.matrix0.Matrix[source]

Bases: Matrix

A generic matrix.

The Matrix class is the base class for all matrix classes. To create a Matrix, first create a MatrixSpace, then coerce a list of elements into the MatrixSpace. See the documentation of MatrixSpace for more details.

EXAMPLES:

We illustrate matrices and matrix spaces. Note that no actual matrix that you make should have class Matrix; the class should always be derived from Matrix.

sage: M = MatrixSpace(CDF,2,3); M
Full MatrixSpace of 2 by 3 dense matrices over Complex Double Field
sage: a = M([1,2,3,  4,5,6]); a
[1.0 2.0 3.0]
[4.0 5.0 6.0]
sage: type(a)
<class 'sage.matrix.matrix_complex_double_dense.Matrix_complex_double_dense'>
sage: parent(a)
Full MatrixSpace of 2 by 3 dense matrices over Complex Double Field

>>> from sage.all import *
>>> M = MatrixSpace(CDF,Integer(2),Integer(3)); M
Full MatrixSpace of 2 by 3 dense matrices over Complex Double Field
>>> a = M([Integer(1),Integer(2),Integer(3),  Integer(4),Integer(5),Integer(6)]); a
[1.0 2.0 3.0]
[4.0 5.0 6.0]
>>> type(a)
<class 'sage.matrix.matrix_complex_double_dense.Matrix_complex_double_dense'>
>>> parent(a)
Full MatrixSpace of 2 by 3 dense matrices over Complex Double Field

M = MatrixSpace(CDF,2,3); M
a = M([1,2,3,  4,5,6]); a
type(a)
parent(a)
sage: matrix(CDF, 2,3, [1,2,3, 4,5,6])
[1.0 2.0 3.0]
[4.0 5.0 6.0]
sage: Mat(CDF,2,3)(range(1,7))
[1.0 2.0 3.0]
[4.0 5.0 6.0]

>>> from sage.all import *
>>> matrix(CDF, Integer(2),Integer(3), [Integer(1),Integer(2),Integer(3), Integer(4),Integer(5),Integer(6)])
[1.0 2.0 3.0]
[4.0 5.0 6.0]
>>> Mat(CDF,Integer(2),Integer(3))(range(Integer(1),Integer(7)))
[1.0 2.0 3.0]
[4.0 5.0 6.0]

matrix(CDF, 2,3, [1,2,3, 4,5,6])
Mat(CDF,2,3)(range(1,7))
>>> from sage.all import *
>>> matrix(CDF, Integer(2),Integer(3), [Integer(1),Integer(2),Integer(3), Integer(4),Integer(5),Integer(6)])
[1.0 2.0 3.0]
[4.0 5.0 6.0]
>>> Mat(CDF,Integer(2),Integer(3))(range(Integer(1),Integer(7)))
[1.0 2.0 3.0]
[4.0 5.0 6.0]

matrix(CDF, 2,3, [1,2,3, 4,5,6])
Mat(CDF,2,3)(range(1,7))
sage: Q.<i,j,k> = QuaternionAlgebra(QQ, -1,-1)
sage: matrix(Q,2,1,[1,2])
[1]
[2]

>>> from sage.all import *
>>> Q = QuaternionAlgebra(QQ, -Integer(1),-Integer(1), names=('i', 'j', 'k',)); (i, j, k,) = Q._first_ngens(3)
>>> matrix(Q,Integer(2),Integer(1),[Integer(1),Integer(2)])
[1]
[2]

Q.<i,j,k> = QuaternionAlgebra(QQ, -1,-1)
matrix(Q,2,1,[1,2])
>>> from sage.all import *
>>> Q = QuaternionAlgebra(QQ, -Integer(1),-Integer(1), names=('i', 'j', 'k',)); (i, j, k,) = Q._first_ngens(3)
>>> matrix(Q,Integer(2),Integer(1),[Integer(1),Integer(2)])
[1]
[2]

Q.<i,j,k> = QuaternionAlgebra(QQ, -1,-1)
matrix(Q,2,1,[1,2])
act_on_polynomial(f)[source]

Return the polynomial f(self*x).

INPUT:

  • self – an nxn matrix

  • f – a polynomial in n variables x=(x1,…,xn)

EXAMPLES:

sage: R.<x,y> = QQ[]
sage: x, y = R.gens()
sage: f = x**2 - y**2
sage: M = MatrixSpace(QQ, 2)
sage: A = M([1,2,3,4])
sage: A.act_on_polynomial(f)
-8*x^2 - 20*x*y - 12*y^2

>>> from sage.all import *
>>> R = QQ['x, y']; (x, y,) = R._first_ngens(2)
>>> x, y = R.gens()
>>> f = x**Integer(2) - y**Integer(2)
>>> M = MatrixSpace(QQ, Integer(2))
>>> A = M([Integer(1),Integer(2),Integer(3),Integer(4)])
>>> A.act_on_polynomial(f)
-8*x^2 - 20*x*y - 12*y^2

R.<x,y> = QQ[]
x, y = R.gens()
f = x**2 - y**2
M = MatrixSpace(QQ, 2)
A = M([1,2,3,4])
A.act_on_polynomial(f)
add_multiple_of_column(i, j, s, start_row=0)[source]

Add s times column j to column i.

EXAMPLES: We add -1 times the third column to the second column of an integer matrix, remembering to start numbering cols at zero:

sage: a = matrix(ZZ,2,3,range(6)); a
[0 1 2]
[3 4 5]
sage: a.add_multiple_of_column(1,2,-1)
sage: a
[ 0 -1  2]
[ 3 -1  5]

>>> from sage.all import *
>>> a = matrix(ZZ,Integer(2),Integer(3),range(Integer(6))); a
[0 1 2]
[3 4 5]
>>> a.add_multiple_of_column(Integer(1),Integer(2),-Integer(1))
>>> a
[ 0 -1  2]
[ 3 -1  5]

a = matrix(ZZ,2,3,range(6)); a
a.add_multiple_of_column(1,2,-1)
a

To add a rational multiple, we first need to change the base ring:

sage: a = a.change_ring(QQ)
sage: a.add_multiple_of_column(1,0,1/3)
sage: a
[ 0 -1  2]
[ 3  0  5]

>>> from sage.all import *
>>> a = a.change_ring(QQ)
>>> a.add_multiple_of_column(Integer(1),Integer(0),Integer(1)/Integer(3))
>>> a
[ 0 -1  2]
[ 3  0  5]

a = a.change_ring(QQ)
a.add_multiple_of_column(1,0,1/3)
a

If not, we get an error message:

sage: a.add_multiple_of_column(1, 0, SR.I())                                # needs sage.symbolic
Traceback (most recent call last):
...
TypeError: Multiplying column by Symbolic Ring element cannot be done over
Rational Field, use change_ring or with_added_multiple_of_column instead.

>>> from sage.all import *
>>> a.add_multiple_of_column(Integer(1), Integer(0), SR.I())                                # needs sage.symbolic
Traceback (most recent call last):
...
TypeError: Multiplying column by Symbolic Ring element cannot be done over
Rational Field, use change_ring or with_added_multiple_of_column instead.

a.add_multiple_of_column(1, 0, SR.I())                                # needs sage.symbolic
add_multiple_of_row(i, j, s, start_col=0)[source]

Add s times row j to row i.

EXAMPLES: We add -3 times the first row to the second row of an integer matrix, remembering to start numbering rows at zero:

sage: a = matrix(ZZ,2,3,range(6)); a
[0 1 2]
[3 4 5]
sage: a.add_multiple_of_row(1,0,-3)
sage: a
[ 0  1  2]
[ 3  1 -1]

>>> from sage.all import *
>>> a = matrix(ZZ,Integer(2),Integer(3),range(Integer(6))); a
[0 1 2]
[3 4 5]
>>> a.add_multiple_of_row(Integer(1),Integer(0),-Integer(3))
>>> a
[ 0  1  2]
[ 3  1 -1]

a = matrix(ZZ,2,3,range(6)); a
a.add_multiple_of_row(1,0,-3)
a

To add a rational multiple, we first need to change the base ring:

sage: a = a.change_ring(QQ)
sage: a.add_multiple_of_row(1,0,1/3)
sage: a
[   0    1    2]
[   3  4/3 -1/3]

>>> from sage.all import *
>>> a = a.change_ring(QQ)
>>> a.add_multiple_of_row(Integer(1),Integer(0),Integer(1)/Integer(3))
>>> a
[   0    1    2]
[   3  4/3 -1/3]

a = a.change_ring(QQ)
a.add_multiple_of_row(1,0,1/3)
a

If not, we get an error message:

sage: a.add_multiple_of_row(1, 0, SR.I())                                   # needs sage.symbolic
Traceback (most recent call last):
...
TypeError: Multiplying row by Symbolic Ring element cannot be done over
Rational Field, use change_ring or with_added_multiple_of_row instead.

>>> from sage.all import *
>>> a.add_multiple_of_row(Integer(1), Integer(0), SR.I())                                   # needs sage.symbolic
Traceback (most recent call last):
...
TypeError: Multiplying row by Symbolic Ring element cannot be done over
Rational Field, use change_ring or with_added_multiple_of_row instead.

a.add_multiple_of_row(1, 0, SR.I())                                   # needs sage.symbolic
add_to_entry(i, j, elt)[source]

Add elt to the entry at position (i, j).

EXAMPLES:

sage: m = matrix(QQ['x,y'], 2, 2)
sage: m.add_to_entry(0, 1, 2)
sage: m
[0 2]
[0 0]

>>> from sage.all import *
>>> m = matrix(QQ['x,y'], Integer(2), Integer(2))
>>> m.add_to_entry(Integer(0), Integer(1), Integer(2))
>>> m
[0 2]
[0 0]

m = matrix(QQ['x,y'], 2, 2)
m.add_to_entry(0, 1, 2)
m
anticommutator(other)[source]

Return the anticommutator self and other.

The anticommutator of two \(n \times n\) matrices \(A\) and \(B\) is defined as \(\{A, B\} := AB + BA\) (sometimes this is written as \([A, B]_+\)).

EXAMPLES:

sage: A = Matrix(ZZ, 2, 2, range(4))
sage: B = Matrix(ZZ, 2, 2, [0, 1, 0, 0])
sage: A.anticommutator(B)
[2 3]
[0 2]
sage: A.anticommutator(B) == B.anticommutator(A)
True
sage: A.commutator(B) + B.anticommutator(A) == 2*A*B
True

>>> from sage.all import *
>>> A = Matrix(ZZ, Integer(2), Integer(2), range(Integer(4)))
>>> B = Matrix(ZZ, Integer(2), Integer(2), [Integer(0), Integer(1), Integer(0), Integer(0)])
>>> A.anticommutator(B)
[2 3]
[0 2]
>>> A.anticommutator(B) == B.anticommutator(A)
True
>>> A.commutator(B) + B.anticommutator(A) == Integer(2)*A*B
True

A = Matrix(ZZ, 2, 2, range(4))
B = Matrix(ZZ, 2, 2, [0, 1, 0, 0])
A.anticommutator(B)
A.anticommutator(B) == B.anticommutator(A)
A.commutator(B) + B.anticommutator(A) == 2*A*B
base_ring()[source]

Return the base ring of the matrix.

EXAMPLES:

sage: m = matrix(QQ, 2, [1,2,3,4])
sage: m.base_ring()
Rational Field

>>> from sage.all import *
>>> m = matrix(QQ, Integer(2), [Integer(1),Integer(2),Integer(3),Integer(4)])
>>> m.base_ring()
Rational Field

m = matrix(QQ, 2, [1,2,3,4])
m.base_ring()
change_ring(ring)[source]

Return the matrix obtained by coercing the entries of this matrix into the given ring.

Always returns a copy (unless self is immutable, in which case returns self).

EXAMPLES:

sage: A = Matrix(QQ, 2, 2, [1/2, 1/3, 1/3, 1/4])
sage: A.parent()
Full MatrixSpace of 2 by 2 dense matrices over Rational Field
sage: A.change_ring(GF(25,'a'))                                             # needs sage.rings.finite_rings
[3 2]
[2 4]
sage: A.change_ring(GF(25,'a')).parent()                                    # needs sage.rings.finite_rings
Full MatrixSpace of 2 by 2 dense matrices
 over Finite Field in a of size 5^2
sage: A.change_ring(ZZ)                                                     # needs sage.rings.finite_rings
Traceback (most recent call last):
...
TypeError: matrix has denominators so can...t change to ZZ

>>> from sage.all import *
>>> A = Matrix(QQ, Integer(2), Integer(2), [Integer(1)/Integer(2), Integer(1)/Integer(3), Integer(1)/Integer(3), Integer(1)/Integer(4)])
>>> A.parent()
Full MatrixSpace of 2 by 2 dense matrices over Rational Field
>>> A.change_ring(GF(Integer(25),'a'))                                             # needs sage.rings.finite_rings
[3 2]
[2 4]
>>> A.change_ring(GF(Integer(25),'a')).parent()                                    # needs sage.rings.finite_rings
Full MatrixSpace of 2 by 2 dense matrices
 over Finite Field in a of size 5^2
>>> A.change_ring(ZZ)                                                     # needs sage.rings.finite_rings
Traceback (most recent call last):
...
TypeError: matrix has denominators so can...t change to ZZ

A = Matrix(QQ, 2, 2, [1/2, 1/3, 1/3, 1/4])
A.parent()
A.change_ring(GF(25,'a'))                                             # needs sage.rings.finite_rings
A.change_ring(GF(25,'a')).parent()                                    # needs sage.rings.finite_rings
A.change_ring(ZZ)                                                     # needs sage.rings.finite_rings

Changing rings preserves subdivisions:

sage: A.subdivide([1], []); A
[1/2 1/3]
[-------]
[1/3 1/4]
sage: A.change_ring(GF(25,'a'))                                             # needs sage.rings.finite_rings
[3 2]
[---]
[2 4]

>>> from sage.all import *
>>> A.subdivide([Integer(1)], []); A
[1/2 1/3]
[-------]
[1/3 1/4]
>>> A.change_ring(GF(Integer(25),'a'))                                             # needs sage.rings.finite_rings
[3 2]
[---]
[2 4]

A.subdivide([1], []); A
A.change_ring(GF(25,'a'))                                             # needs sage.rings.finite_rings
commutator(other)[source]

Return the commutator self*other - other*self.

EXAMPLES:

sage: A = Matrix(ZZ, 2, 2, range(4))
sage: B = Matrix(ZZ, 2, 2, [0, 1, 0, 0])
sage: A.commutator(B)
[-2 -3]
[ 0  2]
sage: A.commutator(B) == -B.commutator(A)
True

>>> from sage.all import *
>>> A = Matrix(ZZ, Integer(2), Integer(2), range(Integer(4)))
>>> B = Matrix(ZZ, Integer(2), Integer(2), [Integer(0), Integer(1), Integer(0), Integer(0)])
>>> A.commutator(B)
[-2 -3]
[ 0  2]
>>> A.commutator(B) == -B.commutator(A)
True

A = Matrix(ZZ, 2, 2, range(4))
B = Matrix(ZZ, 2, 2, [0, 1, 0, 0])
A.commutator(B)
A.commutator(B) == -B.commutator(A)
dense_coefficient_list(order=None)[source]

Return a list of all coefficients of self.

By default, this is the same as list().

INPUT:

  • order – (optional) an ordering of the basis indexing set

EXAMPLES:

sage: A = matrix([[1,2,3], [4,5,6]])
sage: A.dense_coefficient_list()
[1, 2, 3, 4, 5, 6]
sage: A.dense_coefficient_list([(1,2), (1,0), (0,1), (0,2), (0,0), (1,1)])
[6, 4, 2, 3, 1, 5]

>>> from sage.all import *
>>> A = matrix([[Integer(1),Integer(2),Integer(3)], [Integer(4),Integer(5),Integer(6)]])
>>> A.dense_coefficient_list()
[1, 2, 3, 4, 5, 6]
>>> A.dense_coefficient_list([(Integer(1),Integer(2)), (Integer(1),Integer(0)), (Integer(0),Integer(1)), (Integer(0),Integer(2)), (Integer(0),Integer(0)), (Integer(1),Integer(1))])
[6, 4, 2, 3, 1, 5]

A = matrix([[1,2,3], [4,5,6]])
A.dense_coefficient_list()
A.dense_coefficient_list([(1,2), (1,0), (0,1), (0,2), (0,0), (1,1)])
dict(copy=True)[source]

Dictionary of the elements of self with keys pairs (i,j) and values the nonzero entries of self.

INPUT:

  • copy – boolean (default: True); make a copy of the dict corresponding to self

If copy=True, then is safe to change the returned dictionary. Otherwise, this can cause undesired behavior by mutating the dict.

EXAMPLES:

sage: R.<x,y> = QQ[]
sage: a = matrix(R,2,[x,y,0, 0,0,2*x+y]); a
[      x       y       0]
[      0       0 2*x + y]
sage: d = a.dict(); d
{(0, 0): x, (0, 1): y, (1, 2): 2*x + y}

>>> from sage.all import *
>>> R = QQ['x, y']; (x, y,) = R._first_ngens(2)
>>> a = matrix(R,Integer(2),[x,y,Integer(0), Integer(0),Integer(0),Integer(2)*x+y]); a
[      x       y       0]
[      0       0 2*x + y]
>>> d = a.dict(); d
{(0, 0): x, (0, 1): y, (1, 2): 2*x + y}

R.<x,y> = QQ[]
a = matrix(R,2,[x,y,0, 0,0,2*x+y]); a
d = a.dict(); d

Notice that changing the returned list does not change a (the list is a copy):

sage: d[0,0] = 25
sage: a
[      x       y       0]
[      0       0 2*x + y]

>>> from sage.all import *
>>> d[Integer(0),Integer(0)] = Integer(25)
>>> a
[      x       y       0]
[      0       0 2*x + y]

d[0,0] = 25
a
dimensions()[source]

Return the dimensions of this matrix as the tuple (nrows, ncols).

EXAMPLES:

sage: M = matrix([[1,2,3],[4,5,6]])
sage: N = M.transpose()
sage: M.dimensions()
(2, 3)
sage: N.dimensions()
(3, 2)

>>> from sage.all import *
>>> M = matrix([[Integer(1),Integer(2),Integer(3)],[Integer(4),Integer(5),Integer(6)]])
>>> N = M.transpose()
>>> M.dimensions()
(2, 3)
>>> N.dimensions()
(3, 2)

M = matrix([[1,2,3],[4,5,6]])
N = M.transpose()
M.dimensions()
N.dimensions()

AUTHORS:

  • Benjamin Lundell (2012-02-09): examples

inverse_of_unit(algorithm=None)[source]

Return the inverse of this matrix in the same matrix space.

The matrix must be invertible on the base ring. Otherwise, an ArithmeticError is raised.

The computation goes through the matrix of cofactors and avoids division. In particular the base ring does not need to have a fraction field.

INPUT:

  • algorithm – (default: None) either None or 'df' (for division free)

EXAMPLES:

sage: R.<a,b,c,d> = ZZ[]
sage: RR = R.quotient(a*d - b*c - 1)
sage: a,b,c,d = RR.gens()                                                   # needs sage.libs.singular
sage: m = matrix(2, [a,b, c,d])
sage: n = m.inverse_of_unit()                                               # needs sage.libs.singular
sage: m * n                                                                 # needs sage.libs.singular
[1 0]
[0 1]

sage: matrix(RR, 2, 1, [a,b]).inverse_of_unit()                             # needs sage.libs.singular
Traceback (most recent call last):
...
ArithmeticError: self must be a square matrix

sage: matrix(RR, 1, 1, [2]).inverse_of_unit()                               # needs sage.libs.singular
Traceback (most recent call last):
...
ArithmeticError: non-invertible matrix

sage: R = ZZ.cartesian_product(ZZ)
sage: m = matrix(R, 2, [R((2,1)), R((1,1)), R((1,1)), R((1,2))])
sage: m * m.inverse_of_unit()
[(1, 1) (0, 0)]
[(0, 0) (1, 1)]

>>> from sage.all import *
>>> R = ZZ['a, b, c, d']; (a, b, c, d,) = R._first_ngens(4)
>>> RR = R.quotient(a*d - b*c - Integer(1))
>>> a,b,c,d = RR.gens()                                                   # needs sage.libs.singular
>>> m = matrix(Integer(2), [a,b, c,d])
>>> n = m.inverse_of_unit()                                               # needs sage.libs.singular
>>> m * n                                                                 # needs sage.libs.singular
[1 0]
[0 1]

>>> matrix(RR, Integer(2), Integer(1), [a,b]).inverse_of_unit()                             # needs sage.libs.singular
Traceback (most recent call last):
...
ArithmeticError: self must be a square matrix

>>> matrix(RR, Integer(1), Integer(1), [Integer(2)]).inverse_of_unit()                               # needs sage.libs.singular
Traceback (most recent call last):
...
ArithmeticError: non-invertible matrix

>>> R = ZZ.cartesian_product(ZZ)
>>> m = matrix(R, Integer(2), [R((Integer(2),Integer(1))), R((Integer(1),Integer(1))), R((Integer(1),Integer(1))), R((Integer(1),Integer(2)))])
>>> m * m.inverse_of_unit()
[(1, 1) (0, 0)]
[(0, 0) (1, 1)]

R.<a,b,c,d> = ZZ[]
RR = R.quotient(a*d - b*c - 1)
a,b,c,d = RR.gens()                                                   # needs sage.libs.singular
m = matrix(2, [a,b, c,d])
n = m.inverse_of_unit()                                               # needs sage.libs.singular
m * n                                                                 # needs sage.libs.singular
matrix(RR, 2, 1, [a,b]).inverse_of_unit()                             # needs sage.libs.singular
matrix(RR, 1, 1, [2]).inverse_of_unit()                               # needs sage.libs.singular
R = ZZ.cartesian_product(ZZ)
m = matrix(R, 2, [R((2,1)), R((1,1)), R((1,1)), R((1,2))])
m * m.inverse_of_unit()

Tests for Issue #28570:

sage: P = posets.TamariLattice(7)                                           # needs sage.graphs
sage: M = P._hasse_diagram._leq_matrix                                      # needs sage.graphs
sage: M.inverse_of_unit()   # this was very slow, now 1s                    # needs sage.graphs
429 x 429 sparse matrix over Integer Ring...

sage: m = matrix(Zmod(2**2), 1, 1, [1], sparse=True)
sage: mi = ~m; mi
[1]
sage: mi.parent()
Full MatrixSpace of 1 by 1 sparse matrices over Ring of integers modulo 4

>>> from sage.all import *
>>> P = posets.TamariLattice(Integer(7))                                           # needs sage.graphs
>>> M = P._hasse_diagram._leq_matrix                                      # needs sage.graphs
>>> M.inverse_of_unit()   # this was very slow, now 1s                    # needs sage.graphs
429 x 429 sparse matrix over Integer Ring...

>>> m = matrix(Zmod(Integer(2)**Integer(2)), Integer(1), Integer(1), [Integer(1)], sparse=True)
>>> mi = ~m; mi
[1]
>>> mi.parent()
Full MatrixSpace of 1 by 1 sparse matrices over Ring of integers modulo 4

P = posets.TamariLattice(7)                                           # needs sage.graphs
M = P._hasse_diagram._leq_matrix                                      # needs sage.graphs
M.inverse_of_unit()   # this was very slow, now 1s                    # needs sage.graphs
m = matrix(Zmod(2**2), 1, 1, [1], sparse=True)
mi = ~m; mi
mi.parent()
is_alternating()[source]

Return True if self is an alternating matrix.

Here, “alternating matrix” means a square matrix \(A\) satisfying \(A^T = -A\) and such that the diagonal entries of \(A\) are \(0\). Notice that the condition that the diagonal entries be \(0\) is not redundant for matrices over arbitrary ground rings (but it is redundant when \(2\) is invertible in the ground ring). A square matrix \(A\) only required to satisfy \(A^T = -A\) is said to be “skew-symmetric”, and this property is checked by the is_skew_symmetric() method.

EXAMPLES:

sage: m = matrix(QQ, [[0,2], [-2,0]])
sage: m.is_alternating()
True
sage: m = matrix(QQ, [[1,2], [2,1]])
sage: m.is_alternating()
False

>>> from sage.all import *
>>> m = matrix(QQ, [[Integer(0),Integer(2)], [-Integer(2),Integer(0)]])
>>> m.is_alternating()
True
>>> m = matrix(QQ, [[Integer(1),Integer(2)], [Integer(2),Integer(1)]])
>>> m.is_alternating()
False

m = matrix(QQ, [[0,2], [-2,0]])
m.is_alternating()
m = matrix(QQ, [[1,2], [2,1]])
m.is_alternating()

In contrast to the property of being skew-symmetric, the property of being alternating does not tolerate nonzero entries on the diagonal even if they are their own negatives:

sage: n = matrix(Zmod(4), [[0, 1], [-1, 2]])
sage: n.is_alternating()
False

>>> from sage.all import *
>>> n = matrix(Zmod(Integer(4)), [[Integer(0), Integer(1)], [-Integer(1), Integer(2)]])
>>> n.is_alternating()
False

n = matrix(Zmod(4), [[0, 1], [-1, 2]])
n.is_alternating()
is_dense()[source]

Return True if this is a dense matrix.

In Sage, being dense is a property of the underlying representation, not the number of nonzero entries.

EXAMPLES:

sage: matrix(QQ, 2, 2, range(4)).is_dense()
True
sage: matrix(QQ, 2, 2, range(4), sparse=True).is_dense()
False

>>> from sage.all import *
>>> matrix(QQ, Integer(2), Integer(2), range(Integer(4))).is_dense()
True
>>> matrix(QQ, Integer(2), Integer(2), range(Integer(4)), sparse=True).is_dense()
False

matrix(QQ, 2, 2, range(4)).is_dense()
matrix(QQ, 2, 2, range(4), sparse=True).is_dense()
is_hermitian()[source]

Return True if the matrix is equal to its conjugate-transpose.

OUTPUT:

True if the matrix is square and equal to the transpose with every entry conjugated, and False otherwise.

Note that if conjugation has no effect on elements of the base ring (such as for integers), then the is_symmetric() method is equivalent and faster.

This routine is for matrices over exact rings and so may not work properly for matrices over RR or CC. For matrices with approximate entries, the rings of double-precision floating-point numbers, RDF and CDF, are a better choice since the sage.matrix.matrix_double_dense.Matrix_double_dense.is_hermitian() method has a tolerance parameter. This provides control over allowing for minor discrepancies between entries when checking equality.

The result is cached.

EXAMPLES:

sage: # needs sage.rings.number_field
sage: A = matrix(QQbar, [[ 1 + I,  1 - 6*I, -1 - I],
....:                    [-3 - I,     -4*I,     -2],
....:                    [-1 + I, -2 - 8*I,  2 + I]])
sage: A.is_hermitian()
False
sage: B = A * A.conjugate_transpose()
sage: B.is_hermitian()
True

>>> from sage.all import *
>>> # needs sage.rings.number_field
>>> A = matrix(QQbar, [[ Integer(1) + I,  Integer(1) - Integer(6)*I, -Integer(1) - I],
...                    [-Integer(3) - I,     -Integer(4)*I,     -Integer(2)],
...                    [-Integer(1) + I, -Integer(2) - Integer(8)*I,  Integer(2) + I]])
>>> A.is_hermitian()
False
>>> B = A * A.conjugate_transpose()
>>> B.is_hermitian()
True

# needs sage.rings.number_field
A = matrix(QQbar, [[ 1 + I,  1 - 6*I, -1 - I],
                   [-3 - I,     -4*I,     -2],
                   [-1 + I, -2 - 8*I,  2 + I]])
A.is_hermitian()
B = A * A.conjugate_transpose()
B.is_hermitian()

Sage has several fields besides the entire complex numbers where conjugation is non-trivial.

sage: # needs sage.rings.number_field
sage: F.<b> = QuadraticField(-7)
sage: C = matrix(F, [[-2*b - 3,  7*b - 6, -b + 3],
....:                [-2*b - 3, -3*b + 2,   -2*b],
....:                [   b + 1,        0,     -2]])
sage: C.is_hermitian()
False
sage: C = C*C.conjugate_transpose()
sage: C.is_hermitian()
True

>>> from sage.all import *
>>> # needs sage.rings.number_field
>>> F = QuadraticField(-Integer(7), names=('b',)); (b,) = F._first_ngens(1)
>>> C = matrix(F, [[-Integer(2)*b - Integer(3),  Integer(7)*b - Integer(6), -b + Integer(3)],
...                [-Integer(2)*b - Integer(3), -Integer(3)*b + Integer(2),   -Integer(2)*b],
...                [   b + Integer(1),        Integer(0),     -Integer(2)]])
>>> C.is_hermitian()
False
>>> C = C*C.conjugate_transpose()
>>> C.is_hermitian()
True

# needs sage.rings.number_field
F.<b> = QuadraticField(-7)
C = matrix(F, [[-2*b - 3,  7*b - 6, -b + 3],
               [-2*b - 3, -3*b + 2,   -2*b],
               [   b + 1,        0,     -2]])
C.is_hermitian()
C = C*C.conjugate_transpose()
C.is_hermitian()

A matrix that is nearly Hermitian, but for a non-real diagonal entry.

sage: # needs sage.rings.number_field
sage: A = matrix(QQbar, [[    2,   2-I, 1+4*I],
....:                    [  2+I,   3+I, 2-6*I],
....:                    [1-4*I, 2+6*I,     5]])
sage: A.is_hermitian()
False
sage: A[1, 1] = 132
sage: A.is_hermitian()
True

>>> from sage.all import *
>>> # needs sage.rings.number_field
>>> A = matrix(QQbar, [[    Integer(2),   Integer(2)-I, Integer(1)+Integer(4)*I],
...                    [  Integer(2)+I,   Integer(3)+I, Integer(2)-Integer(6)*I],
...                    [Integer(1)-Integer(4)*I, Integer(2)+Integer(6)*I,     Integer(5)]])
>>> A.is_hermitian()
False
>>> A[Integer(1), Integer(1)] = Integer(132)
>>> A.is_hermitian()
True

# needs sage.rings.number_field
A = matrix(QQbar, [[    2,   2-I, 1+4*I],
                   [  2+I,   3+I, 2-6*I],
                   [1-4*I, 2+6*I,     5]])
A.is_hermitian()
A[1, 1] = 132
A.is_hermitian()

Rectangular matrices are never Hermitian.

sage: A = matrix(QQbar, 3, 4)                                               # needs sage.rings.number_field
sage: A.is_hermitian()                                                      # needs sage.rings.number_field
False

>>> from sage.all import *
>>> A = matrix(QQbar, Integer(3), Integer(4))                                               # needs sage.rings.number_field
>>> A.is_hermitian()                                                      # needs sage.rings.number_field
False

A = matrix(QQbar, 3, 4)                                               # needs sage.rings.number_field
A.is_hermitian()                                                      # needs sage.rings.number_field

A square, empty matrix is trivially Hermitian.

sage: A = matrix(QQ, 0, 0)
sage: A.is_hermitian()
True

>>> from sage.all import *
>>> A = matrix(QQ, Integer(0), Integer(0))
>>> A.is_hermitian()
True

A = matrix(QQ, 0, 0)
A.is_hermitian()
is_immutable()[source]

Return True if this matrix is immutable.

See the documentation for self.set_immutable for more details about mutability.

EXAMPLES:

sage: A = Matrix(QQ['t','s'], 2, 2, range(4))
sage: A.is_immutable()
False
sage: A.set_immutable()
sage: A.is_immutable()
True

>>> from sage.all import *
>>> A = Matrix(QQ['t','s'], Integer(2), Integer(2), range(Integer(4)))
>>> A.is_immutable()
False
>>> A.set_immutable()
>>> A.is_immutable()
True

A = Matrix(QQ['t','s'], 2, 2, range(4))
A.is_immutable()
A.set_immutable()
A.is_immutable()
is_invertible()[source]

Return True if this matrix is invertible.

EXAMPLES: The following matrix is invertible over \(\QQ\) but not over \(\ZZ\).

sage: A = MatrixSpace(ZZ, 2)(range(4))
sage: A.is_invertible()
False
sage: A.matrix_over_field().is_invertible()
True

>>> from sage.all import *
>>> A = MatrixSpace(ZZ, Integer(2))(range(Integer(4)))
>>> A.is_invertible()
False
>>> A.matrix_over_field().is_invertible()
True

A = MatrixSpace(ZZ, 2)(range(4))
A.is_invertible()
A.matrix_over_field().is_invertible()

The inverse function is a constructor for matrices over the fraction field, so it can work even if A is not invertible.

sage: ~A   # inverse of A
[-3/2  1/2]
[   1    0]

>>> from sage.all import *
>>> ~A   # inverse of A
[-3/2  1/2]
[   1    0]

~A   # inverse of A

The next matrix is invertible over \(\ZZ\).

sage: A = MatrixSpace(IntegerRing(), 2)([1,10,0,-1])
sage: A.is_invertible()
True
sage: ~A                # compute the inverse
[ 1 10]
[ 0 -1]

>>> from sage.all import *
>>> A = MatrixSpace(IntegerRing(), Integer(2))([Integer(1),Integer(10),Integer(0),-Integer(1)])
>>> A.is_invertible()
True
>>> ~A                # compute the inverse
[ 1 10]
[ 0 -1]

A = MatrixSpace(IntegerRing(), 2)([1,10,0,-1])
A.is_invertible()
~A                # compute the inverse

The following nontrivial matrix is invertible over \(\ZZ[x]\).

sage: R.<x> = PolynomialRing(IntegerRing())
sage: A = MatrixSpace(R, 2)([1,x,0,-1])
sage: A.is_invertible()
True
sage: ~A
[ 1  x]
[ 0 -1]

>>> from sage.all import *
>>> R = PolynomialRing(IntegerRing(), names=('x',)); (x,) = R._first_ngens(1)
>>> A = MatrixSpace(R, Integer(2))([Integer(1),x,Integer(0),-Integer(1)])
>>> A.is_invertible()
True
>>> ~A
[ 1  x]
[ 0 -1]

R.<x> = PolynomialRing(IntegerRing())
A = MatrixSpace(R, 2)([1,x,0,-1])
A.is_invertible()
~A
is_mutable()[source]

Return True if this matrix is mutable.

See the documentation for self.set_immutable for more details about mutability.

EXAMPLES:

sage: A = Matrix(QQ['t','s'], 2, 2, range(4))
sage: A.is_mutable()
True
sage: A.set_immutable()
sage: A.is_mutable()
False

>>> from sage.all import *
>>> A = Matrix(QQ['t','s'], Integer(2), Integer(2), range(Integer(4)))
>>> A.is_mutable()
True
>>> A.set_immutable()
>>> A.is_mutable()
False

A = Matrix(QQ['t','s'], 2, 2, range(4))
A.is_mutable()
A.set_immutable()
A.is_mutable()
is_singular()[source]

Return True if self is singular.

OUTPUT:

A square matrix is singular if it has a zero determinant and this method will return True in exactly this case. When the entries of the matrix come from a field, this is equivalent to having a nontrivial kernel, or lacking an inverse, or having linearly dependent rows, or having linearly dependent columns.

For square matrices over a field the methods is_invertible() and is_singular() are logical opposites. However, it is an error to apply is_singular() to a matrix that is not square, while is_invertible() will always return False for a matrix that is not square.

EXAMPLES:

A singular matrix over the field QQ.

sage: A = matrix(QQ, 4, [-1,2,-3,6, 0,-1,-1,0, -1,1,-5,7, -1,6,5,2])
sage: A.is_singular()
True
sage: A.right_kernel().dimension()
1

>>> from sage.all import *
>>> A = matrix(QQ, Integer(4), [-Integer(1),Integer(2),-Integer(3),Integer(6), Integer(0),-Integer(1),-Integer(1),Integer(0), -Integer(1),Integer(1),-Integer(5),Integer(7), -Integer(1),Integer(6),Integer(5),Integer(2)])
>>> A.is_singular()
True
>>> A.right_kernel().dimension()
1

A = matrix(QQ, 4, [-1,2,-3,6, 0,-1,-1,0, -1,1,-5,7, -1,6,5,2])
A.is_singular()
A.right_kernel().dimension()

A matrix that is not singular, i.e. nonsingular, over a field.

sage: B = matrix(QQ, 4, [1,-3,-1,-5, 2,-5,-2,-7, -2,5,3,4, -1,4,2,6])
sage: B.is_singular()
False
sage: B.left_kernel().dimension()
0

>>> from sage.all import *
>>> B = matrix(QQ, Integer(4), [Integer(1),-Integer(3),-Integer(1),-Integer(5), Integer(2),-Integer(5),-Integer(2),-Integer(7), -Integer(2),Integer(5),Integer(3),Integer(4), -Integer(1),Integer(4),Integer(2),Integer(6)])
>>> B.is_singular()
False
>>> B.left_kernel().dimension()
0

B = matrix(QQ, 4, [1,-3,-1,-5, 2,-5,-2,-7, -2,5,3,4, -1,4,2,6])
B.is_singular()
B.left_kernel().dimension()

For rectangular matrices, invertibility is always False, but asking about singularity will give an error.

sage: C = matrix(QQ, 5, range(30))
sage: C.is_invertible()
False
sage: C.is_singular()
Traceback (most recent call last):
...
ValueError: self must be a square matrix

>>> from sage.all import *
>>> C = matrix(QQ, Integer(5), range(Integer(30)))
>>> C.is_invertible()
False
>>> C.is_singular()
Traceback (most recent call last):
...
ValueError: self must be a square matrix

C = matrix(QQ, 5, range(30))
C.is_invertible()
C.is_singular()

When the base ring is not a field, then a matrix may be both not invertible and not singular.

sage: D = matrix(ZZ, 4, [2,0,-4,8, 2,1,-2,7, 2,5,7,0, 0,1,4,-6])
sage: D.is_invertible()
False
sage: D.is_singular()
False
sage: d = D.determinant(); d
2
sage: d.is_unit()
False

>>> from sage.all import *
>>> D = matrix(ZZ, Integer(4), [Integer(2),Integer(0),-Integer(4),Integer(8), Integer(2),Integer(1),-Integer(2),Integer(7), Integer(2),Integer(5),Integer(7),Integer(0), Integer(0),Integer(1),Integer(4),-Integer(6)])
>>> D.is_invertible()
False
>>> D.is_singular()
False
>>> d = D.determinant(); d
2
>>> d.is_unit()
False

D = matrix(ZZ, 4, [2,0,-4,8, 2,1,-2,7, 2,5,7,0, 0,1,4,-6])
D.is_invertible()
D.is_singular()
d = D.determinant(); d
d.is_unit()
is_skew_hermitian()[source]

Return True if the matrix is equal to the negative of its conjugate transpose.

OUTPUT:

True if the matrix is square and equal to the negative of its conjugate transpose, and False otherwise.

Note that if conjugation has no effect on elements of the base ring (such as for integers), then the is_skew_symmetric() method is equivalent and faster.

This routine is for matrices over exact rings and so may not work properly for matrices over RR or CC. For matrices with approximate entries, the rings of double-precision floating-point numbers, RDF and CDF, are a better choice since the sage.matrix.matrix_double_dense.Matrix_double_dense.is_skew_hermitian() method has a tolerance parameter. This provides control over allowing for minor discrepancies between entries when checking equality.

The result is cached.

EXAMPLES:

sage: A = matrix(QQbar, [[0, -1],                                           # needs sage.rings.number_field
....:                    [1,  0]])
sage: A.is_skew_hermitian()                                                 # needs sage.rings.number_field
True

>>> from sage.all import *
>>> A = matrix(QQbar, [[Integer(0), -Integer(1)],                                           # needs sage.rings.number_field
...                    [Integer(1),  Integer(0)]])
>>> A.is_skew_hermitian()                                                 # needs sage.rings.number_field
True

A = matrix(QQbar, [[0, -1],                                           # needs sage.rings.number_field
                   [1,  0]])
A.is_skew_hermitian()                                                 # needs sage.rings.number_field

A matrix that is nearly skew-Hermitian, but for a non-real diagonal entry.

sage: # needs sage.rings.number_field
sage: A = matrix(QQbar, [[  -I, -1, 1-I],
....:                    [   1,  1,  -1],
....:                    [-1-I,  1,  -I]])
sage: A.is_skew_hermitian()
False
sage: A[1, 1] = -I
sage: A.is_skew_hermitian()
True

>>> from sage.all import *
>>> # needs sage.rings.number_field
>>> A = matrix(QQbar, [[  -I, -Integer(1), Integer(1)-I],
...                    [   Integer(1),  Integer(1),  -Integer(1)],
...                    [-Integer(1)-I,  Integer(1),  -I]])
>>> A.is_skew_hermitian()
False
>>> A[Integer(1), Integer(1)] = -I
>>> A.is_skew_hermitian()
True

# needs sage.rings.number_field
A = matrix(QQbar, [[  -I, -1, 1-I],
                   [   1,  1,  -1],
                   [-1-I,  1,  -I]])
A.is_skew_hermitian()
A[1, 1] = -I
A.is_skew_hermitian()

Rectangular matrices are never skew-Hermitian.

sage: A = matrix(QQbar, 3, 4)                                               # needs sage.rings.number_field
sage: A.is_skew_hermitian()                                                 # needs sage.rings.number_field
False

>>> from sage.all import *
>>> A = matrix(QQbar, Integer(3), Integer(4))                                               # needs sage.rings.number_field
>>> A.is_skew_hermitian()                                                 # needs sage.rings.number_field
False

A = matrix(QQbar, 3, 4)                                               # needs sage.rings.number_field
A.is_skew_hermitian()                                                 # needs sage.rings.number_field

A square, empty matrix is trivially Hermitian.

sage: A = matrix(QQ, 0, 0)
sage: A.is_skew_hermitian()
True

>>> from sage.all import *
>>> A = matrix(QQ, Integer(0), Integer(0))
>>> A.is_skew_hermitian()
True

A = matrix(QQ, 0, 0)
A.is_skew_hermitian()
is_skew_symmetric()[source]

Return True if self is a skew-symmetric matrix.

Here, “skew-symmetric matrix” means a square matrix \(A\) satisfying \(A^T = -A\). It does not require that the diagonal entries of \(A\) are \(0\) (although this automatically follows from \(A^T = -A\) when \(2\) is invertible in the ground ring over which the matrix is considered). Skew-symmetric matrices \(A\) whose diagonal entries are \(0\) are said to be “alternating”, and this property is checked by the is_alternating() method.

EXAMPLES:

sage: m = matrix(QQ, [[0,2], [-2,0]])
sage: m.is_skew_symmetric()
True
sage: m = matrix(QQ, [[1,2], [2,1]])
sage: m.is_skew_symmetric()
False

>>> from sage.all import *
>>> m = matrix(QQ, [[Integer(0),Integer(2)], [-Integer(2),Integer(0)]])
>>> m.is_skew_symmetric()
True
>>> m = matrix(QQ, [[Integer(1),Integer(2)], [Integer(2),Integer(1)]])
>>> m.is_skew_symmetric()
False

m = matrix(QQ, [[0,2], [-2,0]])
m.is_skew_symmetric()
m = matrix(QQ, [[1,2], [2,1]])
m.is_skew_symmetric()

Skew-symmetric is not the same as alternating when \(2\) is a zero-divisor in the ground ring:

sage: n = matrix(Zmod(4), [[0, 1], [-1, 2]])
sage: n.is_skew_symmetric()
True

>>> from sage.all import *
>>> n = matrix(Zmod(Integer(4)), [[Integer(0), Integer(1)], [-Integer(1), Integer(2)]])
>>> n.is_skew_symmetric()
True

n = matrix(Zmod(4), [[0, 1], [-1, 2]])
n.is_skew_symmetric()

but yet the diagonal cannot be completely arbitrary in this case:

sage: n = matrix(Zmod(4), [[0, 1], [-1, 3]])
sage: n.is_skew_symmetric()
False

>>> from sage.all import *
>>> n = matrix(Zmod(Integer(4)), [[Integer(0), Integer(1)], [-Integer(1), Integer(3)]])
>>> n.is_skew_symmetric()
False

n = matrix(Zmod(4), [[0, 1], [-1, 3]])
n.is_skew_symmetric()
is_skew_symmetrizable(return_diag=False, positive=True)[source]

This function takes a square matrix over an ordered integral domain and checks if it is skew-symmetrizable. A matrix \(B\) is skew-symmetrizable iff there exists an invertible diagonal matrix \(D\) such that \(DB\) is skew-symmetric.

Warning

Expects self to be a matrix over an ordered integral domain.

INPUT:

  • return_diag – boolean (default: False); if True and self is skew-symmetrizable the diagonal entries of the matrix \(D\) are returned

  • positive – boolean (default: True); if True, the condition that \(D\) has positive entries is added

OUTPUT:

  • True – if self is skew-symmetrizable and return_diag is False

  • the diagonal entries of a matrix \(D\) such that \(DB\) is skew-symmetric – iff self is skew-symmetrizable and return_diag is True

  • False – iff self is not skew-symmetrizable

EXAMPLES:

sage: matrix([[0,6],[3,0]]).is_skew_symmetrizable(positive=False)
True
sage: matrix([[0,6],[3,0]]).is_skew_symmetrizable(positive=True)
False

sage: M = matrix(4, [0,1,0,0, -1,0,-1,0, 0,2,0,1, 0,0,-1,0]); M
[ 0  1  0  0]
[-1  0 -1  0]
[ 0  2  0  1]
[ 0  0 -1  0]

sage: M.is_skew_symmetrizable(return_diag=True)
[1, 1, 1/2, 1/2]

sage: M2 = diagonal_matrix([1,1,1/2,1/2]) * M; M2
[   0    1    0    0]
[  -1    0   -1    0]
[   0    1    0  1/2]
[   0    0 -1/2    0]

sage: M2.is_skew_symmetric()
True

>>> from sage.all import *
>>> matrix([[Integer(0),Integer(6)],[Integer(3),Integer(0)]]).is_skew_symmetrizable(positive=False)
True
>>> matrix([[Integer(0),Integer(6)],[Integer(3),Integer(0)]]).is_skew_symmetrizable(positive=True)
False

>>> M = matrix(Integer(4), [Integer(0),Integer(1),Integer(0),Integer(0), -Integer(1),Integer(0),-Integer(1),Integer(0), Integer(0),Integer(2),Integer(0),Integer(1), Integer(0),Integer(0),-Integer(1),Integer(0)]); M
[ 0  1  0  0]
[-1  0 -1  0]
[ 0  2  0  1]
[ 0  0 -1  0]

>>> M.is_skew_symmetrizable(return_diag=True)
[1, 1, 1/2, 1/2]

>>> M2 = diagonal_matrix([Integer(1),Integer(1),Integer(1)/Integer(2),Integer(1)/Integer(2)]) * M; M2
[   0    1    0    0]
[  -1    0   -1    0]
[   0    1    0  1/2]
[   0    0 -1/2    0]

>>> M2.is_skew_symmetric()
True

matrix([[0,6],[3,0]]).is_skew_symmetrizable(positive=False)
matrix([[0,6],[3,0]]).is_skew_symmetrizable(positive=True)
M = matrix(4, [0,1,0,0, -1,0,-1,0, 0,2,0,1, 0,0,-1,0]); M
M.is_skew_symmetrizable(return_diag=True)
M2 = diagonal_matrix([1,1,1/2,1/2]) * M; M2
M2.is_skew_symmetric()

REFERENCES:

is_sparse()[source]

Return True if this is a sparse matrix.

In Sage, being sparse is a property of the underlying representation, not the number of nonzero entries.

EXAMPLES:

sage: matrix(QQ, 2, 2, range(4)).is_sparse()
False
sage: matrix(QQ, 2, 2, range(4), sparse=True).is_sparse()
True

>>> from sage.all import *
>>> matrix(QQ, Integer(2), Integer(2), range(Integer(4))).is_sparse()
False
>>> matrix(QQ, Integer(2), Integer(2), range(Integer(4)), sparse=True).is_sparse()
True

matrix(QQ, 2, 2, range(4)).is_sparse()
matrix(QQ, 2, 2, range(4), sparse=True).is_sparse()
is_square()[source]

Return True precisely if this matrix is square, i.e., has the same number of rows and columns.

EXAMPLES:

sage: matrix(QQ, 2, 2, range(4)).is_square()
True
sage: matrix(QQ, 2, 3, range(6)).is_square()
False

>>> from sage.all import *
>>> matrix(QQ, Integer(2), Integer(2), range(Integer(4))).is_square()
True
>>> matrix(QQ, Integer(2), Integer(3), range(Integer(6))).is_square()
False

matrix(QQ, 2, 2, range(4)).is_square()
matrix(QQ, 2, 3, range(6)).is_square()
is_symmetric()[source]

Return True if this is a symmetric matrix.

A symmetric matrix is necessarily square.

EXAMPLES:

sage: m = Matrix(QQ, 2, range(0,4))
sage: m.is_symmetric()
False

sage: m = Matrix(QQ, 2, (1,1,1,1,1,1))
sage: m.is_symmetric()
False

sage: m = Matrix(QQ, 1, (2,))
sage: m.is_symmetric()
True

>>> from sage.all import *
>>> m = Matrix(QQ, Integer(2), range(Integer(0),Integer(4)))
>>> m.is_symmetric()
False

>>> m = Matrix(QQ, Integer(2), (Integer(1),Integer(1),Integer(1),Integer(1),Integer(1),Integer(1)))
>>> m.is_symmetric()
False

>>> m = Matrix(QQ, Integer(1), (Integer(2),))
>>> m.is_symmetric()
True

m = Matrix(QQ, 2, range(0,4))
m.is_symmetric()
m = Matrix(QQ, 2, (1,1,1,1,1,1))
m.is_symmetric()
m = Matrix(QQ, 1, (2,))
m.is_symmetric()
is_symmetrizable(return_diag=False, positive=True)[source]

This function takes a square matrix over an ordered integral domain and checks if it is symmetrizable.

A matrix \(B\) is symmetrizable iff there exists an invertible diagonal matrix \(D\) such that \(DB\) is symmetric.

Warning

Expects self to be a matrix over an ordered integral domain.

INPUT:

  • return_diag – boolean (default: False); if True and self is symmetrizable the diagonal entries of the matrix \(D\) are returned

  • positive – boolean (default: True); if True, the condition that \(D\) has positive entries is added

OUTPUT:

  • True – if self is symmetrizable and return_diag is False

  • the diagonal entries of a matrix \(D\) such that \(DB\) is symmetric – iff self is symmetrizable and return_diag is True

  • False – iff self is not symmetrizable

EXAMPLES:

sage: matrix([[0,6],[3,0]]).is_symmetrizable(positive=False)
True

sage: matrix([[0,6],[3,0]]).is_symmetrizable(positive=True)
True

sage: matrix([[0,6],[0,0]]).is_symmetrizable(return_diag=True)
False

sage: matrix([2]).is_symmetrizable(positive=True)
True

sage: matrix([[1,2],[3,4]]).is_symmetrizable(return_diag=true)
[1, 2/3]

>>> from sage.all import *
>>> matrix([[Integer(0),Integer(6)],[Integer(3),Integer(0)]]).is_symmetrizable(positive=False)
True

>>> matrix([[Integer(0),Integer(6)],[Integer(3),Integer(0)]]).is_symmetrizable(positive=True)
True

>>> matrix([[Integer(0),Integer(6)],[Integer(0),Integer(0)]]).is_symmetrizable(return_diag=True)
False

>>> matrix([Integer(2)]).is_symmetrizable(positive=True)
True

>>> matrix([[Integer(1),Integer(2)],[Integer(3),Integer(4)]]).is_symmetrizable(return_diag=true)
[1, 2/3]

matrix([[0,6],[3,0]]).is_symmetrizable(positive=False)
matrix([[0,6],[3,0]]).is_symmetrizable(positive=True)
matrix([[0,6],[0,0]]).is_symmetrizable(return_diag=True)
matrix([2]).is_symmetrizable(positive=True)
matrix([[1,2],[3,4]]).is_symmetrizable(return_diag=true)

REFERENCES:

is_unit()[source]

Return True if this matrix is invertible.

EXAMPLES: The following matrix is invertible over \(\QQ\) but not over \(\ZZ\).

sage: A = MatrixSpace(ZZ, 2)(range(4))
sage: A.is_invertible()
False
sage: A.matrix_over_field().is_invertible()
True

>>> from sage.all import *
>>> A = MatrixSpace(ZZ, Integer(2))(range(Integer(4)))
>>> A.is_invertible()
False
>>> A.matrix_over_field().is_invertible()
True

A = MatrixSpace(ZZ, 2)(range(4))
A.is_invertible()
A.matrix_over_field().is_invertible()

The inverse function is a constructor for matrices over the fraction field, so it can work even if A is not invertible.

sage: ~A   # inverse of A
[-3/2  1/2]
[   1    0]

>>> from sage.all import *
>>> ~A   # inverse of A
[-3/2  1/2]
[   1    0]

~A   # inverse of A

The next matrix is invertible over \(\ZZ\).

sage: A = MatrixSpace(IntegerRing(), 2)([1,10,0,-1])
sage: A.is_invertible()
True
sage: ~A                # compute the inverse
[ 1 10]
[ 0 -1]

>>> from sage.all import *
>>> A = MatrixSpace(IntegerRing(), Integer(2))([Integer(1),Integer(10),Integer(0),-Integer(1)])
>>> A.is_invertible()
True
>>> ~A                # compute the inverse
[ 1 10]
[ 0 -1]

A = MatrixSpace(IntegerRing(), 2)([1,10,0,-1])
A.is_invertible()
~A                # compute the inverse

The following nontrivial matrix is invertible over \(\ZZ[x]\).

sage: R.<x> = PolynomialRing(IntegerRing())
sage: A = MatrixSpace(R, 2)([1,x,0,-1])
sage: A.is_invertible()
True
sage: ~A
[ 1  x]
[ 0 -1]

>>> from sage.all import *
>>> R = PolynomialRing(IntegerRing(), names=('x',)); (x,) = R._first_ngens(1)
>>> A = MatrixSpace(R, Integer(2))([Integer(1),x,Integer(0),-Integer(1)])
>>> A.is_invertible()
True
>>> ~A
[ 1  x]
[ 0 -1]

R.<x> = PolynomialRing(IntegerRing())
A = MatrixSpace(R, 2)([1,x,0,-1])
A.is_invertible()
~A
items()[source]

Return an iterable of ((i,j), value) elements.

This may (but is not guaranteed to) suppress zero values.

EXAMPLES:

sage: a = matrix(QQ['x,y'], 2, range(6), sparse=True); a
[0 1 2]
[3 4 5]
sage: list(a.items())
[((0, 1), 1), ((0, 2), 2), ((1, 0), 3), ((1, 1), 4), ((1, 2), 5)]

>>> from sage.all import *
>>> a = matrix(QQ['x,y'], Integer(2), range(Integer(6)), sparse=True); a
[0 1 2]
[3 4 5]
>>> list(a.items())
[((0, 1), 1), ((0, 2), 2), ((1, 0), 3), ((1, 1), 4), ((1, 2), 5)]

a = matrix(QQ['x,y'], 2, range(6), sparse=True); a
list(a.items())
iterates(v, n, rows=True)[source]

Let \(A\) be this matrix and \(v\) be a free module element. If rows is True, return a matrix whose rows are the entries of the following vectors:

\[v, v A, v A^2, \dots, v A^{n-1}.\]

If rows is False, return a matrix whose columns are the entries of the following vectors:

\[v, Av, A^2 v, \dots, A^{n-1} v.\]

INPUT:

  • v – free module element

  • n – nonnegative integer

EXAMPLES:

sage: A = matrix(ZZ, 2, [1,1,3,5]); A
[1 1]
[3 5]
sage: v = vector([1,0])
sage: A.iterates(v, 0)
[]
sage: A.iterates(v, 5)
[  1   0]
[  1   1]
[  4   6]
[ 22  34]
[124 192]

>>> from sage.all import *
>>> A = matrix(ZZ, Integer(2), [Integer(1),Integer(1),Integer(3),Integer(5)]); A
[1 1]
[3 5]
>>> v = vector([Integer(1),Integer(0)])
>>> A.iterates(v, Integer(0))
[]
>>> A.iterates(v, Integer(5))
[  1   0]
[  1   1]
[  4   6]
[ 22  34]
[124 192]

A = matrix(ZZ, 2, [1,1,3,5]); A
v = vector([1,0])
A.iterates(v, 0)
A.iterates(v, 5)

Another example:

sage: a = matrix(ZZ, 3, range(9)); a
[0 1 2]
[3 4 5]
[6 7 8]
sage: v = vector([1,0,0])
sage: a.iterates(v, 4)
[  1   0   0]
[  0   1   2]
[ 15  18  21]
[180 234 288]
sage: a.iterates(v, 4, rows=False)
[  1   0  15 180]
[  0   3  42 558]
[  0   6  69 936]

>>> from sage.all import *
>>> a = matrix(ZZ, Integer(3), range(Integer(9))); a
[0 1 2]
[3 4 5]
[6 7 8]
>>> v = vector([Integer(1),Integer(0),Integer(0)])
>>> a.iterates(v, Integer(4))
[  1   0   0]
[  0   1   2]
[ 15  18  21]
[180 234 288]
>>> a.iterates(v, Integer(4), rows=False)
[  1   0  15 180]
[  0   3  42 558]
[  0   6  69 936]

a = matrix(ZZ, 3, range(9)); a
v = vector([1,0,0])
a.iterates(v, 4)
a.iterates(v, 4, rows=False)
linear_combination_of_columns(v)[source]

Return the linear combination of the columns of self given by the coefficients in the list v.

INPUT:

  • v – a list of scalars. The length can be less than the number of columns of self but not greater.

OUTPUT:

The vector (or free module element) that is a linear combination of the columns of self. If the list of scalars has fewer entries than the number of columns, additional zeros are appended to the list until it has as many entries as the number of columns.

EXAMPLES:

sage: a = matrix(ZZ, 2, 3, range(6)); a
[0 1 2]
[3 4 5]
sage: a.linear_combination_of_columns([1,1,1])
(3, 12)

sage: a.linear_combination_of_columns([0,0,0])
(0, 0)

sage: a.linear_combination_of_columns([1/2,2/3,3/4])
(13/6, 95/12)

>>> from sage.all import *
>>> a = matrix(ZZ, Integer(2), Integer(3), range(Integer(6))); a
[0 1 2]
[3 4 5]
>>> a.linear_combination_of_columns([Integer(1),Integer(1),Integer(1)])
(3, 12)

>>> a.linear_combination_of_columns([Integer(0),Integer(0),Integer(0)])
(0, 0)

>>> a.linear_combination_of_columns([Integer(1)/Integer(2),Integer(2)/Integer(3),Integer(3)/Integer(4)])
(13/6, 95/12)

a = matrix(ZZ, 2, 3, range(6)); a
a.linear_combination_of_columns([1,1,1])
a.linear_combination_of_columns([0,0,0])
a.linear_combination_of_columns([1/2,2/3,3/4])

The list v can be anything that is iterable. Perhaps most naturally, a vector may be used.

sage: v = vector(ZZ, [1,2,3])
sage: a.linear_combination_of_columns(v)
(8, 26)

>>> from sage.all import *
>>> v = vector(ZZ, [Integer(1),Integer(2),Integer(3)])
>>> a.linear_combination_of_columns(v)
(8, 26)

v = vector(ZZ, [1,2,3])
a.linear_combination_of_columns(v)

We check that a matrix with no columns behaves properly.

sage: matrix(QQ, 2, 0).linear_combination_of_columns([])
(0, 0)

>>> from sage.all import *
>>> matrix(QQ, Integer(2), Integer(0)).linear_combination_of_columns([])
(0, 0)

matrix(QQ, 2, 0).linear_combination_of_columns([])

The object returned is a vector, or a free module element.

sage: B = matrix(ZZ, 4, 3, range(12))
sage: w = B.linear_combination_of_columns([-1,2,-3])
sage: w
(-4, -10, -16, -22)
sage: w.parent()
Ambient free module of rank 4 over the principal ideal domain Integer Ring
sage: x = B.linear_combination_of_columns([1/2,1/3,1/4])
sage: x
(5/6, 49/12, 22/3, 127/12)
sage: x.parent()
Vector space of dimension 4 over Rational Field

>>> from sage.all import *
>>> B = matrix(ZZ, Integer(4), Integer(3), range(Integer(12)))
>>> w = B.linear_combination_of_columns([-Integer(1),Integer(2),-Integer(3)])
>>> w
(-4, -10, -16, -22)
>>> w.parent()
Ambient free module of rank 4 over the principal ideal domain Integer Ring
>>> x = B.linear_combination_of_columns([Integer(1)/Integer(2),Integer(1)/Integer(3),Integer(1)/Integer(4)])
>>> x
(5/6, 49/12, 22/3, 127/12)
>>> x.parent()
Vector space of dimension 4 over Rational Field

B = matrix(ZZ, 4, 3, range(12))
w = B.linear_combination_of_columns([-1,2,-3])
w
w.parent()
x = B.linear_combination_of_columns([1/2,1/3,1/4])
x
x.parent()

The length of v can be less than the number of columns, but not greater.

sage: A = matrix(QQ, 3, 5, range(15))
sage: A.linear_combination_of_columns([1,-2,3,-4])
(-8, -18, -28)
sage: A.linear_combination_of_columns([1,2,3,4,5,6])
Traceback (most recent call last):
...
ValueError: length of v must be at most the number of columns of self

>>> from sage.all import *
>>> A = matrix(QQ, Integer(3), Integer(5), range(Integer(15)))
>>> A.linear_combination_of_columns([Integer(1),-Integer(2),Integer(3),-Integer(4)])
(-8, -18, -28)
>>> A.linear_combination_of_columns([Integer(1),Integer(2),Integer(3),Integer(4),Integer(5),Integer(6)])
Traceback (most recent call last):
...
ValueError: length of v must be at most the number of columns of self

A = matrix(QQ, 3, 5, range(15))
A.linear_combination_of_columns([1,-2,3,-4])
A.linear_combination_of_columns([1,2,3,4,5,6])
linear_combination_of_rows(v)[source]

Return the linear combination of the rows of self given by the coefficients in the list v.

INPUT:

  • v – a list of scalars. The length can be less than the number of rows of self but not greater.

OUTPUT:

The vector (or free module element) that is a linear combination of the rows of self. If the list of scalars has fewer entries than the number of rows, additional zeros are appended to the list until it has as many entries as the number of rows.

EXAMPLES:

sage: a = matrix(ZZ, 2, 3, range(6)); a
[0 1 2]
[3 4 5]
sage: a.linear_combination_of_rows([1,2])
(6, 9, 12)

sage: a.linear_combination_of_rows([0,0])
(0, 0, 0)

sage: a.linear_combination_of_rows([1/2,2/3])
(2, 19/6, 13/3)

>>> from sage.all import *
>>> a = matrix(ZZ, Integer(2), Integer(3), range(Integer(6))); a
[0 1 2]
[3 4 5]
>>> a.linear_combination_of_rows([Integer(1),Integer(2)])
(6, 9, 12)

>>> a.linear_combination_of_rows([Integer(0),Integer(0)])
(0, 0, 0)

>>> a.linear_combination_of_rows([Integer(1)/Integer(2),Integer(2)/Integer(3)])
(2, 19/6, 13/3)

a = matrix(ZZ, 2, 3, range(6)); a
a.linear_combination_of_rows([1,2])
a.linear_combination_of_rows([0,0])
a.linear_combination_of_rows([1/2,2/3])

The list v can be anything that is iterable. Perhaps most naturally, a vector may be used.

sage: v = vector(ZZ, [1,2])
sage: a.linear_combination_of_rows(v)
(6, 9, 12)

>>> from sage.all import *
>>> v = vector(ZZ, [Integer(1),Integer(2)])
>>> a.linear_combination_of_rows(v)
(6, 9, 12)

v = vector(ZZ, [1,2])
a.linear_combination_of_rows(v)

We check that a matrix with no rows behaves properly.

sage: matrix(QQ, 0, 2).linear_combination_of_rows([])
(0, 0)

>>> from sage.all import *
>>> matrix(QQ, Integer(0), Integer(2)).linear_combination_of_rows([])
(0, 0)

matrix(QQ, 0, 2).linear_combination_of_rows([])

The object returned is a vector, or a free module element.

sage: B = matrix(ZZ, 4, 3, range(12))
sage: w = B.linear_combination_of_rows([-1,2,-3,4])
sage: w
(24, 26, 28)
sage: w.parent()
Ambient free module of rank 3 over the principal ideal domain Integer Ring
sage: x = B.linear_combination_of_rows([1/2,1/3,1/4,1/5])
sage: x
(43/10, 67/12, 103/15)
sage: x.parent()
Vector space of dimension 3 over Rational Field

>>> from sage.all import *
>>> B = matrix(ZZ, Integer(4), Integer(3), range(Integer(12)))
>>> w = B.linear_combination_of_rows([-Integer(1),Integer(2),-Integer(3),Integer(4)])
>>> w
(24, 26, 28)
>>> w.parent()
Ambient free module of rank 3 over the principal ideal domain Integer Ring
>>> x = B.linear_combination_of_rows([Integer(1)/Integer(2),Integer(1)/Integer(3),Integer(1)/Integer(4),Integer(1)/Integer(5)])
>>> x
(43/10, 67/12, 103/15)
>>> x.parent()
Vector space of dimension 3 over Rational Field

B = matrix(ZZ, 4, 3, range(12))
w = B.linear_combination_of_rows([-1,2,-3,4])
w
w.parent()
x = B.linear_combination_of_rows([1/2,1/3,1/4,1/5])
x
x.parent()

The length of v can be less than the number of rows, but not greater.

sage: A = matrix(QQ, 3, 4, range(12))
sage: A.linear_combination_of_rows([2,3])
(12, 17, 22, 27)
sage: A.linear_combination_of_rows([1,2,3,4])
Traceback (most recent call last):
...
ValueError: length of v must be at most the number of rows of self

>>> from sage.all import *
>>> A = matrix(QQ, Integer(3), Integer(4), range(Integer(12)))
>>> A.linear_combination_of_rows([Integer(2),Integer(3)])
(12, 17, 22, 27)
>>> A.linear_combination_of_rows([Integer(1),Integer(2),Integer(3),Integer(4)])
Traceback (most recent call last):
...
ValueError: length of v must be at most the number of rows of self

A = matrix(QQ, 3, 4, range(12))
A.linear_combination_of_rows([2,3])
A.linear_combination_of_rows([1,2,3,4])
list()[source]

List of the elements of self ordered by elements in each row. It is safe to change the returned list.

Warning

This function returns a list of the entries in the matrix self. It does not return a list of the rows of self, so it is different than the output of list(self), which returns [self[0],self[1],...].

EXAMPLES:

sage: R.<x,y> = QQ[]
sage: a = matrix(R,2,[x,y,x*y, y,x,2*x+y]); a
[      x       y     x*y]
[      y       x 2*x + y]
sage: v = a.list(); v
[x, y, x*y, y, x, 2*x + y]

>>> from sage.all import *
>>> R = QQ['x, y']; (x, y,) = R._first_ngens(2)
>>> a = matrix(R,Integer(2),[x,y,x*y, y,x,Integer(2)*x+y]); a
[      x       y     x*y]
[      y       x 2*x + y]
>>> v = a.list(); v
[x, y, x*y, y, x, 2*x + y]

R.<x,y> = QQ[]
a = matrix(R,2,[x,y,x*y, y,x,2*x+y]); a
v = a.list(); v

Note that list(a) is different than a.list():

sage: a.list()
[x, y, x*y, y, x, 2*x + y]
sage: list(a)
[(x, y, x*y), (y, x, 2*x + y)]

>>> from sage.all import *
>>> a.list()
[x, y, x*y, y, x, 2*x + y]
>>> list(a)
[(x, y, x*y), (y, x, 2*x + y)]

a.list()
list(a)

Notice that changing the returned list does not change a (the list is a copy):

sage: v[0] = 25
sage: a
[      x       y     x*y]
[      y       x 2*x + y]

>>> from sage.all import *
>>> v[Integer(0)] = Integer(25)
>>> a
[      x       y     x*y]
[      y       x 2*x + y]

v[0] = 25
a
mod(p)[source]

Return matrix mod \(p\), over the reduced ring.

EXAMPLES:

sage: M = matrix(ZZ, 2, 2, [5, 9, 13, 15])
sage: M.mod(7)
[5 2]
[6 1]
sage: parent(M.mod(7))
Full MatrixSpace of 2 by 2 dense matrices over Ring of integers modulo 7

>>> from sage.all import *
>>> M = matrix(ZZ, Integer(2), Integer(2), [Integer(5), Integer(9), Integer(13), Integer(15)])
>>> M.mod(Integer(7))
[5 2]
[6 1]
>>> parent(M.mod(Integer(7)))
Full MatrixSpace of 2 by 2 dense matrices over Ring of integers modulo 7

M = matrix(ZZ, 2, 2, [5, 9, 13, 15])
M.mod(7)
parent(M.mod(7))
monomial_coefficients(copy=True)[source]

Dictionary of the elements of self with keys pairs (i,j) and values the nonzero entries of self.

INPUT:

  • copy – boolean (default: True); make a copy of the dict corresponding to self

If copy=True, then is safe to change the returned dictionary. Otherwise, this can cause undesired behavior by mutating the dict.

EXAMPLES:

sage: R.<x,y> = QQ[]
sage: a = matrix(R,2,[x,y,0, 0,0,2*x+y]); a
[      x       y       0]
[      0       0 2*x + y]
sage: d = a.dict(); d
{(0, 0): x, (0, 1): y, (1, 2): 2*x + y}

>>> from sage.all import *
>>> R = QQ['x, y']; (x, y,) = R._first_ngens(2)
>>> a = matrix(R,Integer(2),[x,y,Integer(0), Integer(0),Integer(0),Integer(2)*x+y]); a
[      x       y       0]
[      0       0 2*x + y]
>>> d = a.dict(); d
{(0, 0): x, (0, 1): y, (1, 2): 2*x + y}

R.<x,y> = QQ[]
a = matrix(R,2,[x,y,0, 0,0,2*x+y]); a
d = a.dict(); d

Notice that changing the returned list does not change a (the list is a copy):

sage: d[0,0] = 25
sage: a
[      x       y       0]
[      0       0 2*x + y]

>>> from sage.all import *
>>> d[Integer(0),Integer(0)] = Integer(25)
>>> a
[      x       y       0]
[      0       0 2*x + y]

d[0,0] = 25
a
multiplicative_order()[source]

Return the multiplicative order of this matrix, which must therefore be invertible.

Only implemented over finite fields and over \(\ZZ\).

EXAMPLES:

Over finite fields:

sage: A = matrix(GF(59), 3, [10,56,39,53,56,33,58,24,55])
sage: A.multiplicative_order()                                              # needs sage.libs.pari
580
sage: (A^580).is_one()
True

sage: B = matrix(GF(10007^3, 'b'), 0)                                       # needs sage.rings.finite_rings
sage: B.multiplicative_order()                                              # needs sage.rings.finite_rings
1

sage: # needs sage.rings.finite_rings
sage: M = MatrixSpace(GF(11^2, 'e'), 5)
sage: E = M.random_element()
sage: while E.det() == 0:
....:     E = M.random_element()
sage: (E^E.multiplicative_order()).is_one()
True

>>> from sage.all import *
>>> A = matrix(GF(Integer(59)), Integer(3), [Integer(10),Integer(56),Integer(39),Integer(53),Integer(56),Integer(33),Integer(58),Integer(24),Integer(55)])
>>> A.multiplicative_order()                                              # needs sage.libs.pari
580
>>> (A**Integer(580)).is_one()
True

>>> B = matrix(GF(Integer(10007)**Integer(3), 'b'), Integer(0))                                       # needs sage.rings.finite_rings
>>> B.multiplicative_order()                                              # needs sage.rings.finite_rings
1

>>> # needs sage.rings.finite_rings
>>> M = MatrixSpace(GF(Integer(11)**Integer(2), 'e'), Integer(5))
>>> E = M.random_element()
>>> while E.det() == Integer(0):
...     E = M.random_element()
>>> (E**E.multiplicative_order()).is_one()
True

A = matrix(GF(59), 3, [10,56,39,53,56,33,58,24,55])
A.multiplicative_order()                                              # needs sage.libs.pari
(A^580).is_one()
B = matrix(GF(10007^3, 'b'), 0)                                       # needs sage.rings.finite_rings
B.multiplicative_order()                                              # needs sage.rings.finite_rings
# needs sage.rings.finite_rings
M = MatrixSpace(GF(11^2, 'e'), 5)
E = M.random_element()
while E.det() == 0:
    E = M.random_element()
(E^E.multiplicative_order()).is_one()

Over \(\ZZ\):

sage: m = matrix(ZZ, 2, 2, [-1,1,-1,0])
sage: m.multiplicative_order()                                              # needs sage.libs.pari
3

sage: m = posets.ChainPoset(6).coxeter_transformation()                     # needs sage.combinat sage.graphs
sage: m.multiplicative_order()                                              # needs sage.combinat sage.graphs sage.groups
7

sage: P = posets.TamariLattice(4).coxeter_transformation()                  # needs sage.combinat sage.graphs
sage: P.multiplicative_order()                                              # needs sage.combinat sage.graphs sage.groups
10

sage: M = matrix(ZZ, 2, 2, [1, 1, 0, 1])
sage: M.multiplicative_order()                                              # needs sage.libs.pari
+Infinity

sage: for k in range(600):                                                  # needs sage.groups sage.modular
....:     m = SL2Z.random_element()
....:     o = m.multiplicative_order()
....:     if o != Infinity and m**o != SL2Z.one():
....:         raise RuntimeError

sage: m24 = matrix.companion(cyclotomic_polynomial(24))
sage: def val(i, j):
....:     if i < j:
....:         return 0
....:     elif i == j:
....:         return 1
....:     else:
....:         return ZZ.random_element(-100,100)
sage: rnd = matrix(ZZ, 8, 8, val)
sage: (rnd * m24 * rnd.inverse_of_unit()).multiplicative_order()            # needs sage.libs.pari
24

>>> from sage.all import *
>>> m = matrix(ZZ, Integer(2), Integer(2), [-Integer(1),Integer(1),-Integer(1),Integer(0)])
>>> m.multiplicative_order()                                              # needs sage.libs.pari
3

>>> m = posets.ChainPoset(Integer(6)).coxeter_transformation()                     # needs sage.combinat sage.graphs
>>> m.multiplicative_order()                                              # needs sage.combinat sage.graphs sage.groups
7

>>> P = posets.TamariLattice(Integer(4)).coxeter_transformation()                  # needs sage.combinat sage.graphs
>>> P.multiplicative_order()                                              # needs sage.combinat sage.graphs sage.groups
10

>>> M = matrix(ZZ, Integer(2), Integer(2), [Integer(1), Integer(1), Integer(0), Integer(1)])
>>> M.multiplicative_order()                                              # needs sage.libs.pari
+Infinity

>>> for k in range(Integer(600)):                                                  # needs sage.groups sage.modular
...     m = SL2Z.random_element()
...     o = m.multiplicative_order()
...     if o != Infinity and m**o != SL2Z.one():
...         raise RuntimeError

>>> m24 = matrix.companion(cyclotomic_polynomial(Integer(24)))
>>> def val(i, j):
...     if i < j:
...         return Integer(0)
...     elif i == j:
...         return Integer(1)
...     else:
...         return ZZ.random_element(-Integer(100),Integer(100))
>>> rnd = matrix(ZZ, Integer(8), Integer(8), val)
>>> (rnd * m24 * rnd.inverse_of_unit()).multiplicative_order()            # needs sage.libs.pari
24

m = matrix(ZZ, 2, 2, [-1,1,-1,0])
m.multiplicative_order()                                              # needs sage.libs.pari
m = posets.ChainPoset(6).coxeter_transformation()                     # needs sage.combinat sage.graphs
m.multiplicative_order()                                              # needs sage.combinat sage.graphs sage.groups
P = posets.TamariLattice(4).coxeter_transformation()                  # needs sage.combinat sage.graphs
P.multiplicative_order()                                              # needs sage.combinat sage.graphs sage.groups
M = matrix(ZZ, 2, 2, [1, 1, 0, 1])
M.multiplicative_order()                                              # needs sage.libs.pari
for k in range(600):                                                  # needs sage.groups sage.modular
    m = SL2Z.random_element()
    o = m.multiplicative_order()
    if o != Infinity and m**o != SL2Z.one():
        raise RuntimeError
m24 = matrix.companion(cyclotomic_polynomial(24))
def val(i, j):
    if i < j:
        return 0
    elif i == j:
        return 1
    else:
        return ZZ.random_element(-100,100)
rnd = matrix(ZZ, 8, 8, val)
(rnd * m24 * rnd.inverse_of_unit()).multiplicative_order()            # needs sage.libs.pari

REFERENCES:

mutate(k)[source]

Mutates self at row and column index k.

Warning

Only makes sense if self is skew-symmetrizable.

INPUT:

  • k – integer at which row/column self is mutated

EXAMPLES:

Mutation of the B-matrix of the quiver of type \(A_3\):

sage: M = matrix(ZZ, 3, [0,1,0,-1,0,-1,0,1,0]); M
[ 0  1  0]
[-1  0 -1]
[ 0  1  0]

sage: M.mutate(0); M
[ 0 -1  0]
[ 1  0 -1]
[ 0  1  0]

sage: M.mutate(1); M
[ 0  1 -1]
[-1  0  1]
[ 1 -1  0]

sage: M = matrix(ZZ, 6, [0,1,0,-1,0,-1,0,1,0,1,0,0,0,1,0,0,0,1]); M
[ 0  1  0]
[-1  0 -1]
[ 0  1  0]
[ 1  0  0]
[ 0  1  0]
[ 0  0  1]

sage: M.mutate(0); M
[ 0 -1  0]
[ 1  0 -1]
[ 0  1  0]
[-1  1  0]
[ 0  1  0]
[ 0  0  1]

>>> from sage.all import *
>>> M = matrix(ZZ, Integer(3), [Integer(0),Integer(1),Integer(0),-Integer(1),Integer(0),-Integer(1),Integer(0),Integer(1),Integer(0)]); M
[ 0  1  0]
[-1  0 -1]
[ 0  1  0]

>>> M.mutate(Integer(0)); M
[ 0 -1  0]
[ 1  0 -1]
[ 0  1  0]

>>> M.mutate(Integer(1)); M
[ 0  1 -1]
[-1  0  1]
[ 1 -1  0]

>>> M = matrix(ZZ, Integer(6), [Integer(0),Integer(1),Integer(0),-Integer(1),Integer(0),-Integer(1),Integer(0),Integer(1),Integer(0),Integer(1),Integer(0),Integer(0),Integer(0),Integer(1),Integer(0),Integer(0),Integer(0),Integer(1)]); M
[ 0  1  0]
[-1  0 -1]
[ 0  1  0]
[ 1  0  0]
[ 0  1  0]
[ 0  0  1]

>>> M.mutate(Integer(0)); M
[ 0 -1  0]
[ 1  0 -1]
[ 0  1  0]
[-1  1  0]
[ 0  1  0]
[ 0  0  1]

M = matrix(ZZ, 3, [0,1,0,-1,0,-1,0,1,0]); M
M.mutate(0); M
M.mutate(1); M
M = matrix(ZZ, 6, [0,1,0,-1,0,-1,0,1,0,1,0,0,0,1,0,0,0,1]); M
M.mutate(0); M

REFERENCES:

ncols()[source]

Return the number of columns of this matrix.

EXAMPLES:

sage: M = MatrixSpace(QQ, 2, 3)
sage: A = M([1,2,3, 4,5,6])
sage: A
[1 2 3]
[4 5 6]
sage: A.ncols()
3
sage: A.nrows()
2

>>> from sage.all import *
>>> M = MatrixSpace(QQ, Integer(2), Integer(3))
>>> A = M([Integer(1),Integer(2),Integer(3), Integer(4),Integer(5),Integer(6)])
>>> A
[1 2 3]
[4 5 6]
>>> A.ncols()
3
>>> A.nrows()
2

M = MatrixSpace(QQ, 2, 3)
A = M([1,2,3, 4,5,6])
A
A.ncols()
A.nrows()

AUTHORS:

  • Naqi Jaffery (2006-01-24): examples

nonpivots()[source]

Return the list of \(i\) such that the \(i\)-th column of self is NOT a pivot column of the reduced row echelon form of self.

OUTPUT: sorted tuple of (Python) integers

EXAMPLES:

sage: a = matrix(QQ, 3, 3, range(9)); a
[0 1 2]
[3 4 5]
[6 7 8]
sage: a.echelon_form()
[ 1  0 -1]
[ 0  1  2]
[ 0  0  0]
sage: a.nonpivots()
(2,)

>>> from sage.all import *
>>> a = matrix(QQ, Integer(3), Integer(3), range(Integer(9))); a
[0 1 2]
[3 4 5]
[6 7 8]
>>> a.echelon_form()
[ 1  0 -1]
[ 0  1  2]
[ 0  0  0]
>>> a.nonpivots()
(2,)

a = matrix(QQ, 3, 3, range(9)); a
a.echelon_form()
a.nonpivots()
nonzero_positions(copy=True, column_order=False)[source]

Return the sorted list of pairs (i,j) such that self[i,j] != 0.

INPUT:

  • copy – boolean (default: True); it is safe to change the resulting list (unless you give the option copy=False)

  • column_order – boolean (default: False); if True, returns the list of pairs (i,j) such that self[i,j] != 0, but sorted by columns, i.e., column j=0 entries occur first, then column j=1 entries, etc.

EXAMPLES:

sage: a = matrix(QQ, 2,3, [1,2,0,2,0,0]); a
[1 2 0]
[2 0 0]
sage: a.nonzero_positions()
[(0, 0), (0, 1), (1, 0)]
sage: a.nonzero_positions(copy=False)
[(0, 0), (0, 1), (1, 0)]
sage: a.nonzero_positions(column_order=True)
[(0, 0), (1, 0), (0, 1)]
sage: a = matrix(QQ, 2,3, [1,2,0,2,0,0], sparse=True); a
[1 2 0]
[2 0 0]
sage: a.nonzero_positions()
[(0, 0), (0, 1), (1, 0)]
sage: a.nonzero_positions(copy=False)
[(0, 0), (0, 1), (1, 0)]
sage: a.nonzero_positions(column_order=True)
[(0, 0), (1, 0), (0, 1)]

>>> from sage.all import *
>>> a = matrix(QQ, Integer(2),Integer(3), [Integer(1),Integer(2),Integer(0),Integer(2),Integer(0),Integer(0)]); a
[1 2 0]
[2 0 0]
>>> a.nonzero_positions()
[(0, 0), (0, 1), (1, 0)]
>>> a.nonzero_positions(copy=False)
[(0, 0), (0, 1), (1, 0)]
>>> a.nonzero_positions(column_order=True)
[(0, 0), (1, 0), (0, 1)]
>>> a = matrix(QQ, Integer(2),Integer(3), [Integer(1),Integer(2),Integer(0),Integer(2),Integer(0),Integer(0)], sparse=True); a
[1 2 0]
[2 0 0]
>>> a.nonzero_positions()
[(0, 0), (0, 1), (1, 0)]
>>> a.nonzero_positions(copy=False)
[(0, 0), (0, 1), (1, 0)]
>>> a.nonzero_positions(column_order=True)
[(0, 0), (1, 0), (0, 1)]

a = matrix(QQ, 2,3, [1,2,0,2,0,0]); a
a.nonzero_positions()
a.nonzero_positions(copy=False)
a.nonzero_positions(column_order=True)
a = matrix(QQ, 2,3, [1,2,0,2,0,0], sparse=True); a
a.nonzero_positions()
a.nonzero_positions(copy=False)
a.nonzero_positions(column_order=True)
nonzero_positions_in_column(i)[source]

Return a sorted list of the integers j such that self[j,i] is nonzero, i.e., such that the j-th position of the i-th column is nonzero.

INPUT:

  • i – integer

OUTPUT: list

EXAMPLES:

sage: a = matrix(QQ, 3,2, [1,2,0,2,0,0]); a
[1 2]
[0 2]
[0 0]
sage: a.nonzero_positions_in_column(0)
[0]
sage: a.nonzero_positions_in_column(1)
[0, 1]

>>> from sage.all import *
>>> a = matrix(QQ, Integer(3),Integer(2), [Integer(1),Integer(2),Integer(0),Integer(2),Integer(0),Integer(0)]); a
[1 2]
[0 2]
[0 0]
>>> a.nonzero_positions_in_column(Integer(0))
[0]
>>> a.nonzero_positions_in_column(Integer(1))
[0, 1]

a = matrix(QQ, 3,2, [1,2,0,2,0,0]); a
a.nonzero_positions_in_column(0)
a.nonzero_positions_in_column(1)

You will get an IndexError if you select an invalid column:

sage: a.nonzero_positions_in_column(2)
Traceback (most recent call last):
...
IndexError: matrix column index out of range

>>> from sage.all import *
>>> a.nonzero_positions_in_column(Integer(2))
Traceback (most recent call last):
...
IndexError: matrix column index out of range

a.nonzero_positions_in_column(2)
nonzero_positions_in_row(i)[source]

Return the integers j such that self[i,j] is nonzero, i.e., such that the j-th position of the i-th row is nonzero.

INPUT:

  • i – integer

OUTPUT: list

EXAMPLES:

sage: a = matrix(QQ, 3,2, [1,2,0,2,0,0]); a
[1 2]
[0 2]
[0 0]
sage: a.nonzero_positions_in_row(0)
[0, 1]
sage: a.nonzero_positions_in_row(1)
[1]
sage: a.nonzero_positions_in_row(2)
[]

>>> from sage.all import *
>>> a = matrix(QQ, Integer(3),Integer(2), [Integer(1),Integer(2),Integer(0),Integer(2),Integer(0),Integer(0)]); a
[1 2]
[0 2]
[0 0]
>>> a.nonzero_positions_in_row(Integer(0))
[0, 1]
>>> a.nonzero_positions_in_row(Integer(1))
[1]
>>> a.nonzero_positions_in_row(Integer(2))
[]

a = matrix(QQ, 3,2, [1,2,0,2,0,0]); a
a.nonzero_positions_in_row(0)
a.nonzero_positions_in_row(1)
a.nonzero_positions_in_row(2)
nrows()[source]

Return the number of rows of this matrix.

EXAMPLES:

sage: M = MatrixSpace(QQ,6,7)
sage: A = M([1,2,3,4,5,6,7, 22,3/4,34,11,7,5,3, 99,65,1/2,2/3,3/5,4/5,5/6, 9,8/9, 9/8,7/6,6/7,76,4, 0,9,8,7,6,5,4, 123,99,91,28,6,1024,1])
sage: A
[   1    2    3    4    5    6    7]
[  22  3/4   34   11    7    5    3]
[  99   65  1/2  2/3  3/5  4/5  5/6]
[   9  8/9  9/8  7/6  6/7   76    4]
[   0    9    8    7    6    5    4]
[ 123   99   91   28    6 1024    1]
sage: A.ncols()
7
sage: A.nrows()
6

>>> from sage.all import *
>>> M = MatrixSpace(QQ,Integer(6),Integer(7))
>>> A = M([Integer(1),Integer(2),Integer(3),Integer(4),Integer(5),Integer(6),Integer(7), Integer(22),Integer(3)/Integer(4),Integer(34),Integer(11),Integer(7),Integer(5),Integer(3), Integer(99),Integer(65),Integer(1)/Integer(2),Integer(2)/Integer(3),Integer(3)/Integer(5),Integer(4)/Integer(5),Integer(5)/Integer(6), Integer(9),Integer(8)/Integer(9), Integer(9)/Integer(8),Integer(7)/Integer(6),Integer(6)/Integer(7),Integer(76),Integer(4), Integer(0),Integer(9),Integer(8),Integer(7),Integer(6),Integer(5),Integer(4), Integer(123),Integer(99),Integer(91),Integer(28),Integer(6),Integer(1024),Integer(1)])
>>> A
[   1    2    3    4    5    6    7]
[  22  3/4   34   11    7    5    3]
[  99   65  1/2  2/3  3/5  4/5  5/6]
[   9  8/9  9/8  7/6  6/7   76    4]
[   0    9    8    7    6    5    4]
[ 123   99   91   28    6 1024    1]
>>> A.ncols()
7
>>> A.nrows()
6

M = MatrixSpace(QQ,6,7)
A = M([1,2,3,4,5,6,7, 22,3/4,34,11,7,5,3, 99,65,1/2,2/3,3/5,4/5,5/6, 9,8/9, 9/8,7/6,6/7,76,4, 0,9,8,7,6,5,4, 123,99,91,28,6,1024,1])
A
A.ncols()
A.nrows()

AUTHORS:

  • Naqi Jaffery (2006-01-24): examples

permute_columns(permutation)[source]

Permute the columns of self by applying the permutation group element permutation.

As permutation group elements act on integers \(\{1,\dots,n\}\), columns are considered numbered from 1 for this operation.

INPUT:

  • permutation – a PermutationGroupElement

EXAMPLES: We create a matrix:

sage: M = matrix(ZZ, [[1,0,0,0,0],[0,2,0,0,0],[0,0,3,0,0],[0,0,0,4,0],[0,0,0,0,5]])
sage: M
[1 0 0 0 0]
[0 2 0 0 0]
[0 0 3 0 0]
[0 0 0 4 0]
[0 0 0 0 5]

>>> from sage.all import *
>>> M = matrix(ZZ, [[Integer(1),Integer(0),Integer(0),Integer(0),Integer(0)],[Integer(0),Integer(2),Integer(0),Integer(0),Integer(0)],[Integer(0),Integer(0),Integer(3),Integer(0),Integer(0)],[Integer(0),Integer(0),Integer(0),Integer(4),Integer(0)],[Integer(0),Integer(0),Integer(0),Integer(0),Integer(5)]])
>>> M
[1 0 0 0 0]
[0 2 0 0 0]
[0 0 3 0 0]
[0 0 0 4 0]
[0 0 0 0 5]

M = matrix(ZZ, [[1,0,0,0,0],[0,2,0,0,0],[0,0,3,0,0],[0,0,0,4,0],[0,0,0,0,5]])
M

Next of all, create a permutation group element and act on M with it:

sage: # needs sage.groups
sage: G = PermutationGroup(['(1,2,3)(4,5)', '(1,2,3,4,5)'])
sage: sigma, tau = G.gens()
sage: sigma
(1,2,3)(4,5)
sage: M.permute_columns(sigma)
sage: M
[0 0 1 0 0]
[2 0 0 0 0]
[0 3 0 0 0]
[0 0 0 0 4]
[0 0 0 5 0]

>>> from sage.all import *
>>> # needs sage.groups
>>> G = PermutationGroup(['(1,2,3)(4,5)', '(1,2,3,4,5)'])
>>> sigma, tau = G.gens()
>>> sigma
(1,2,3)(4,5)
>>> M.permute_columns(sigma)
>>> M
[0 0 1 0 0]
[2 0 0 0 0]
[0 3 0 0 0]
[0 0 0 0 4]
[0 0 0 5 0]

# needs sage.groups
G = PermutationGroup(['(1,2,3)(4,5)', '(1,2,3,4,5)'])
sigma, tau = G.gens()
sigma
M.permute_columns(sigma)
M
permute_rows(permutation)[source]

Permute the rows of self by applying the permutation group element permutation.

As permutation group elements act on integers \(\{1,\dots,n\}\), rows are considered numbered from 1 for this operation.

INPUT:

  • permutation – a PermutationGroupElement

EXAMPLES: We create a matrix:

sage: M = matrix(ZZ, [[1,0,0,0,0],[0,2,0,0,0],[0,0,3,0,0],[0,0,0,4,0],[0,0,0,0,5]])
sage: M
[1 0 0 0 0]
[0 2 0 0 0]
[0 0 3 0 0]
[0 0 0 4 0]
[0 0 0 0 5]

>>> from sage.all import *
>>> M = matrix(ZZ, [[Integer(1),Integer(0),Integer(0),Integer(0),Integer(0)],[Integer(0),Integer(2),Integer(0),Integer(0),Integer(0)],[Integer(0),Integer(0),Integer(3),Integer(0),Integer(0)],[Integer(0),Integer(0),Integer(0),Integer(4),Integer(0)],[Integer(0),Integer(0),Integer(0),Integer(0),Integer(5)]])
>>> M
[1 0 0 0 0]
[0 2 0 0 0]
[0 0 3 0 0]
[0 0 0 4 0]
[0 0 0 0 5]

M = matrix(ZZ, [[1,0,0,0,0],[0,2,0,0,0],[0,0,3,0,0],[0,0,0,4,0],[0,0,0,0,5]])
M

Next of all, create a permutation group element and act on M:

sage: # needs sage.groups
sage: G = PermutationGroup(['(1,2,3)(4,5)', '(1,2,3,4,5)'])
sage: sigma, tau = G.gens()
sage: sigma
(1,2,3)(4,5)
sage: M.permute_rows(sigma)
sage: M
[0 2 0 0 0]
[0 0 3 0 0]
[1 0 0 0 0]
[0 0 0 0 5]
[0 0 0 4 0]

>>> from sage.all import *
>>> # needs sage.groups
>>> G = PermutationGroup(['(1,2,3)(4,5)', '(1,2,3,4,5)'])
>>> sigma, tau = G.gens()
>>> sigma
(1,2,3)(4,5)
>>> M.permute_rows(sigma)
>>> M
[0 2 0 0 0]
[0 0 3 0 0]
[1 0 0 0 0]
[0 0 0 0 5]
[0 0 0 4 0]

# needs sage.groups
G = PermutationGroup(['(1,2,3)(4,5)', '(1,2,3,4,5)'])
sigma, tau = G.gens()
sigma
M.permute_rows(sigma)
M
permute_rows_and_columns(row_permutation, column_permutation)[source]

Permute the rows and columns of self by applying the permutation group elements row_permutation and column_permutation respectively.

As permutation group elements act on integers \(\{1,\dots,n\}\), rows and columns are considered numbered from 1 for this operation.

INPUT:

  • row_permutation – a PermutationGroupElement

  • column_permutation – a PermutationGroupElement

OUTPUT: a matrix

EXAMPLES: We create a matrix:

sage: M = matrix(ZZ, [[1,0,0,0,0],[0,2,0,0,0],[0,0,3,0,0],[0,0,0,4,0],[0,0,0,0,5]])
sage: M
[1 0 0 0 0]
[0 2 0 0 0]
[0 0 3 0 0]
[0 0 0 4 0]
[0 0 0 0 5]

>>> from sage.all import *
>>> M = matrix(ZZ, [[Integer(1),Integer(0),Integer(0),Integer(0),Integer(0)],[Integer(0),Integer(2),Integer(0),Integer(0),Integer(0)],[Integer(0),Integer(0),Integer(3),Integer(0),Integer(0)],[Integer(0),Integer(0),Integer(0),Integer(4),Integer(0)],[Integer(0),Integer(0),Integer(0),Integer(0),Integer(5)]])
>>> M
[1 0 0 0 0]
[0 2 0 0 0]
[0 0 3 0 0]
[0 0 0 4 0]
[0 0 0 0 5]

M = matrix(ZZ, [[1,0,0,0,0],[0,2,0,0,0],[0,0,3,0,0],[0,0,0,4,0],[0,0,0,0,5]])
M

Next of all, create a permutation group element and act on M:

sage: # needs sage.groups
sage: G = PermutationGroup(['(1,2,3)(4,5)', '(1,2,3,4,5)'])
sage: sigma, tau = G.gens()
sage: sigma
(1,2,3)(4,5)
sage: M.permute_rows_and_columns(sigma,tau)
sage: M
[2 0 0 0 0]
[0 3 0 0 0]
[0 0 0 0 1]
[0 0 0 5 0]
[0 0 4 0 0]

>>> from sage.all import *
>>> # needs sage.groups
>>> G = PermutationGroup(['(1,2,3)(4,5)', '(1,2,3,4,5)'])
>>> sigma, tau = G.gens()
>>> sigma
(1,2,3)(4,5)
>>> M.permute_rows_and_columns(sigma,tau)
>>> M
[2 0 0 0 0]
[0 3 0 0 0]
[0 0 0 0 1]
[0 0 0 5 0]
[0 0 4 0 0]

# needs sage.groups
G = PermutationGroup(['(1,2,3)(4,5)', '(1,2,3,4,5)'])
sigma, tau = G.gens()
sigma
M.permute_rows_and_columns(sigma,tau)
M
pivots()[source]

Return the pivot column positions of this matrix.

OUTPUT: a tuple of Python integers: the position of the first nonzero entry in each row of the echelon form.

This returns a tuple so it is immutable; see Issue #10752.

EXAMPLES:

sage: A = matrix(QQ, 2, 2, range(4))
sage: A.pivots()
(0, 1)

>>> from sage.all import *
>>> A = matrix(QQ, Integer(2), Integer(2), range(Integer(4)))
>>> A.pivots()
(0, 1)

A = matrix(QQ, 2, 2, range(4))
A.pivots()
rank()[source]

Return the rank of this matrix.

EXAMPLES:

sage: m = matrix(GF(7), 5, range(25))
sage: m.rank()
2

>>> from sage.all import *
>>> m = matrix(GF(Integer(7)), Integer(5), range(Integer(25)))
>>> m.rank()
2

m = matrix(GF(7), 5, range(25))
m.rank()

Rank is not implemented over the integers modulo a composite yet.:

sage: m = matrix(Integers(4), 2, [2,2,2,2])
sage: m.rank()
Traceback (most recent call last):
...
NotImplementedError: Echelon form not implemented over 'Ring of integers modulo 4'.

>>> from sage.all import *
>>> m = matrix(Integers(Integer(4)), Integer(2), [Integer(2),Integer(2),Integer(2),Integer(2)])
>>> m.rank()
Traceback (most recent call last):
...
NotImplementedError: Echelon form not implemented over 'Ring of integers modulo 4'.

m = matrix(Integers(4), 2, [2,2,2,2])
m.rank()
rescale_col(i, s, start_row=0)[source]

Replace \(i\)-th col of self by \(s\) times \(i\)-th col of self.

INPUT:

  • i – \(i\)-th column

  • s – scalar

  • start_row – only rescale entries at this row and lower

EXAMPLES: We rescale the last column of a matrix over the rational numbers:

sage: a = matrix(QQ, 2, 3, range(6)); a
[0 1 2]
[3 4 5]
sage: a.rescale_col(2, 1/2); a
[  0   1   1]
[  3   4 5/2]
sage: R.<x> = QQ[]

>>> from sage.all import *
>>> a = matrix(QQ, Integer(2), Integer(3), range(Integer(6))); a
[0 1 2]
[3 4 5]
>>> a.rescale_col(Integer(2), Integer(1)/Integer(2)); a
[  0   1   1]
[  3   4 5/2]
>>> R = QQ['x']; (x,) = R._first_ngens(1)

a = matrix(QQ, 2, 3, range(6)); a
a.rescale_col(2, 1/2); a
R.<x> = QQ[]

We rescale the last column of a matrix over a polynomial ring:

sage: a = matrix(R, 2, 3, [1,x,x^2,x^3,x^4,x^5]); a
[  1   x x^2]
[x^3 x^4 x^5]
sage: a.rescale_col(2, 1/2); a
[      1       x 1/2*x^2]
[    x^3     x^4 1/2*x^5]

>>> from sage.all import *
>>> a = matrix(R, Integer(2), Integer(3), [Integer(1),x,x**Integer(2),x**Integer(3),x**Integer(4),x**Integer(5)]); a
[  1   x x^2]
[x^3 x^4 x^5]
>>> a.rescale_col(Integer(2), Integer(1)/Integer(2)); a
[      1       x 1/2*x^2]
[    x^3     x^4 1/2*x^5]

a = matrix(R, 2, 3, [1,x,x^2,x^3,x^4,x^5]); a
a.rescale_col(2, 1/2); a

We try and fail to rescale a matrix over the integers by a non-integer:

sage: a = matrix(ZZ, 2, 3, [0,1,2, 3,4,4]); a
[0 1 2]
[3 4 4]
sage: a.rescale_col(2, 1/2)
Traceback (most recent call last):
...
TypeError: Rescaling column by Rational Field element cannot be done
over Integer Ring, use change_ring or with_rescaled_col instead.

>>> from sage.all import *
>>> a = matrix(ZZ, Integer(2), Integer(3), [Integer(0),Integer(1),Integer(2), Integer(3),Integer(4),Integer(4)]); a
[0 1 2]
[3 4 4]
>>> a.rescale_col(Integer(2), Integer(1)/Integer(2))
Traceback (most recent call last):
...
TypeError: Rescaling column by Rational Field element cannot be done
over Integer Ring, use change_ring or with_rescaled_col instead.

a = matrix(ZZ, 2, 3, [0,1,2, 3,4,4]); a
a.rescale_col(2, 1/2)

To rescale the matrix by 1/2, you must change the base ring to the rationals:

sage: a = a.change_ring(QQ); a
[0 1 2]
[3 4 4]
sage: a.rescale_col(2,1/2); a
[0 1 1]
[3 4 2]

>>> from sage.all import *
>>> a = a.change_ring(QQ); a
[0 1 2]
[3 4 4]
>>> a.rescale_col(Integer(2),Integer(1)/Integer(2)); a
[0 1 1]
[3 4 2]

a = a.change_ring(QQ); a
a.rescale_col(2,1/2); a
rescale_row(i, s, start_col=0)[source]

Replace \(i\)-th row of self by \(s\) times \(i\)-th row of self.

INPUT:

  • i – \(i\)-th row

  • s – scalar

  • start_col – only rescale entries at this column and to the right

EXAMPLES: We rescale the second row of a matrix over the rational numbers:

sage: a = matrix(QQ, 3, range(6)); a
[0 1]
[2 3]
[4 5]
sage: a.rescale_row(1, 1/2); a
[ 0   1]
[ 1 3/2]
[ 4   5]

>>> from sage.all import *
>>> a = matrix(QQ, Integer(3), range(Integer(6))); a
[0 1]
[2 3]
[4 5]
>>> a.rescale_row(Integer(1), Integer(1)/Integer(2)); a
[ 0   1]
[ 1 3/2]
[ 4   5]

a = matrix(QQ, 3, range(6)); a
a.rescale_row(1, 1/2); a

We rescale the second row of a matrix over a polynomial ring:

sage: R.<x> = QQ[]
sage: a = matrix(R, 3, [1,x,x^2,x^3,x^4,x^5]); a
[  1   x]
[x^2 x^3]
[x^4 x^5]
sage: a.rescale_row(1, 1/2); a
[      1       x]
[1/2*x^2 1/2*x^3]
[    x^4     x^5]

>>> from sage.all import *
>>> R = QQ['x']; (x,) = R._first_ngens(1)
>>> a = matrix(R, Integer(3), [Integer(1),x,x**Integer(2),x**Integer(3),x**Integer(4),x**Integer(5)]); a
[  1   x]
[x^2 x^3]
[x^4 x^5]
>>> a.rescale_row(Integer(1), Integer(1)/Integer(2)); a
[      1       x]
[1/2*x^2 1/2*x^3]
[    x^4     x^5]

R.<x> = QQ[]
a = matrix(R, 3, [1,x,x^2,x^3,x^4,x^5]); a
a.rescale_row(1, 1/2); a

We try and fail to rescale a matrix over the integers by a non-integer:

sage: a = matrix(ZZ, 2, 3, [0,1,2, 3,4,4]); a
[0 1 2]
[3 4 4]
sage: a.rescale_row(1, 1/2)
Traceback (most recent call last):
...
TypeError: Rescaling row by Rational Field element cannot be done
over Integer Ring, use change_ring or with_rescaled_row instead.

>>> from sage.all import *
>>> a = matrix(ZZ, Integer(2), Integer(3), [Integer(0),Integer(1),Integer(2), Integer(3),Integer(4),Integer(4)]); a
[0 1 2]
[3 4 4]
>>> a.rescale_row(Integer(1), Integer(1)/Integer(2))
Traceback (most recent call last):
...
TypeError: Rescaling row by Rational Field element cannot be done
over Integer Ring, use change_ring or with_rescaled_row instead.

a = matrix(ZZ, 2, 3, [0,1,2, 3,4,4]); a
a.rescale_row(1, 1/2)

To rescale the matrix by 1/2, you must change the base ring to the rationals:

sage: a = a.change_ring(QQ); a
[0 1 2]
[3 4 4]
sage: a.rescale_col(1, 1/2); a
[  0 1/2   2]
[  3   2   4]

>>> from sage.all import *
>>> a = a.change_ring(QQ); a
[0 1 2]
[3 4 4]
>>> a.rescale_col(Integer(1), Integer(1)/Integer(2)); a
[  0 1/2   2]
[  3   2   4]

a = a.change_ring(QQ); a
a.rescale_col(1, 1/2); a
reverse_rows_and_columns()[source]

Reverse the row order and column order of this matrix.

This method transforms a matrix \(m_{i,j}\) with \(0 \leq i < nrows\) and \(0 \leq j < ncols\) into \(m_{nrows - i - 1, ncols - j - 1}\).

EXAMPLES:

sage: m = matrix(ZZ, 2, 2, range(4))
sage: m.reverse_rows_and_columns()
sage: m
[3 2]
[1 0]

sage: m = matrix(ZZ, 2, 3, range(6), sparse=True)
sage: m.reverse_rows_and_columns()
sage: m
[5 4 3]
[2 1 0]
sage: m = matrix(ZZ, 3, 2, range(6), sparse=True)
sage: m.reverse_rows_and_columns()
sage: m
[5 4]
[3 2]
[1 0]
sage: m.reverse_rows_and_columns()
sage: m
[0 1]
[2 3]
[4 5]

sage: m = matrix(QQ, 3, 2, [1/i for i in range(1,7)])
sage: m.reverse_rows_and_columns()
sage: m
[1/6 1/5]
[1/4 1/3]
[1/2   1]

sage: R.<x,y> = ZZ['x,y']
sage: m = matrix(R, 3, 3, lambda i,j: x**i*y**j, sparse=True)
sage: m.reverse_rows_and_columns()
sage: m
[x^2*y^2   x^2*y     x^2]
[  x*y^2     x*y       x]
[    y^2       y       1]

>>> from sage.all import *
>>> m = matrix(ZZ, Integer(2), Integer(2), range(Integer(4)))
>>> m.reverse_rows_and_columns()
>>> m
[3 2]
[1 0]

>>> m = matrix(ZZ, Integer(2), Integer(3), range(Integer(6)), sparse=True)
>>> m.reverse_rows_and_columns()
>>> m
[5 4 3]
[2 1 0]
>>> m = matrix(ZZ, Integer(3), Integer(2), range(Integer(6)), sparse=True)
>>> m.reverse_rows_and_columns()
>>> m
[5 4]
[3 2]
[1 0]
>>> m.reverse_rows_and_columns()
>>> m
[0 1]
[2 3]
[4 5]

>>> m = matrix(QQ, Integer(3), Integer(2), [Integer(1)/i for i in range(Integer(1),Integer(7))])
>>> m.reverse_rows_and_columns()
>>> m
[1/6 1/5]
[1/4 1/3]
[1/2   1]

>>> R = ZZ['x,y']; (x, y,) = R._first_ngens(2)
>>> m = matrix(R, Integer(3), Integer(3), lambda i,j: x**i*y**j, sparse=True)
>>> m.reverse_rows_and_columns()
>>> m
[x^2*y^2   x^2*y     x^2]
[  x*y^2     x*y       x]
[    y^2       y       1]

m = matrix(ZZ, 2, 2, range(4))
m.reverse_rows_and_columns()
m
m = matrix(ZZ, 2, 3, range(6), sparse=True)
m.reverse_rows_and_columns()
m
m = matrix(ZZ, 3, 2, range(6), sparse=True)
m.reverse_rows_and_columns()
m
m.reverse_rows_and_columns()
m
m = matrix(QQ, 3, 2, [1/i for i in range(1,7)])
m.reverse_rows_and_columns()
m
R.<x,y> = ZZ['x,y']
m = matrix(R, 3, 3, lambda i,j: x**i*y**j, sparse=True)
m.reverse_rows_and_columns()
m

If the matrix is immutable, the method raises an error:

sage: m = matrix(ZZ, 2, [1, 3, -2, 4])
sage: m.set_immutable()
sage: m.reverse_rows_and_columns()
Traceback (most recent call last):
...
ValueError: matrix is immutable; please change a copy
instead (i.e., use copy(M) to change a copy of M).

>>> from sage.all import *
>>> m = matrix(ZZ, Integer(2), [Integer(1), Integer(3), -Integer(2), Integer(4)])
>>> m.set_immutable()
>>> m.reverse_rows_and_columns()
Traceback (most recent call last):
...
ValueError: matrix is immutable; please change a copy
instead (i.e., use copy(M) to change a copy of M).

m = matrix(ZZ, 2, [1, 3, -2, 4])
m.set_immutable()
m.reverse_rows_and_columns()
set_col_to_multiple_of_col(i, j, s)[source]

Set column i equal to s times column j.

EXAMPLES: We change the second column to -3 times the first column.

sage: a = matrix(ZZ, 2, 3, range(6)); a
[0 1 2]
[3 4 5]
sage: a.set_col_to_multiple_of_col(1, 0, -3)
sage: a
[ 0  0  2]
[ 3 -9  5]

>>> from sage.all import *
>>> a = matrix(ZZ, Integer(2), Integer(3), range(Integer(6))); a
[0 1 2]
[3 4 5]
>>> a.set_col_to_multiple_of_col(Integer(1), Integer(0), -Integer(3))
>>> a
[ 0  0  2]
[ 3 -9  5]

a = matrix(ZZ, 2, 3, range(6)); a
a.set_col_to_multiple_of_col(1, 0, -3)
a

If we try to multiply a column by a rational number, we get an error message:

sage: a.set_col_to_multiple_of_col(1, 0, 1/2)
Traceback (most recent call last):
...
TypeError: Multiplying column by Rational Field element cannot be done over Integer Ring, use change_ring or with_col_set_to_multiple_of_col instead.

>>> from sage.all import *
>>> a.set_col_to_multiple_of_col(Integer(1), Integer(0), Integer(1)/Integer(2))
Traceback (most recent call last):
...
TypeError: Multiplying column by Rational Field element cannot be done over Integer Ring, use change_ring or with_col_set_to_multiple_of_col instead.

a.set_col_to_multiple_of_col(1, 0, 1/2)
set_immutable()[source]

Call this function to set the matrix as immutable.

Matrices are always mutable by default, i.e., you can change their entries using A[i,j] = x. However, mutable matrices aren’t hashable, so can’t be used as keys in dictionaries, etc. Also, often when implementing a class, you might compute a matrix associated to it, e.g., the matrix of a Hecke operator. If you return this matrix to the user you’re really returning a reference and the user could then change an entry; this could be confusing. Thus you should set such a matrix immutable.

EXAMPLES:

sage: A = Matrix(QQ, 2, 2, range(4))
sage: A.is_mutable()
True
sage: A[0,0] = 10
sage: A
[10   1]
[ 2   3]

>>> from sage.all import *
>>> A = Matrix(QQ, Integer(2), Integer(2), range(Integer(4)))
>>> A.is_mutable()
True
>>> A[Integer(0),Integer(0)] = Integer(10)
>>> A
[10   1]
[ 2   3]

A = Matrix(QQ, 2, 2, range(4))
A.is_mutable()
A[0,0] = 10
A

Mutable matrices are not hashable, so can’t be used as keys for dictionaries:

sage: hash(A)
Traceback (most recent call last):
...
TypeError: mutable matrices are unhashable
sage: v = {A:1}
Traceback (most recent call last):
...
TypeError: mutable matrices are unhashable

>>> from sage.all import *
>>> hash(A)
Traceback (most recent call last):
...
TypeError: mutable matrices are unhashable
>>> v = {A:Integer(1)}
Traceback (most recent call last):
...
TypeError: mutable matrices are unhashable

hash(A)
v = {A:1}

If we make A immutable it suddenly is hashable.

sage: A.set_immutable()
sage: A.is_mutable()
False
sage: A[0,0] = 10
Traceback (most recent call last):
...
ValueError: matrix is immutable; please change a copy instead
(i.e., use copy(M) to change a copy of M).
sage: hash(A) #random
12
sage: v = {A:1}; v
{[10  1]
 [ 2  3]: 1}

>>> from sage.all import *
>>> A.set_immutable()
>>> A.is_mutable()
False
>>> A[Integer(0),Integer(0)] = Integer(10)
Traceback (most recent call last):
...
ValueError: matrix is immutable; please change a copy instead
(i.e., use copy(M) to change a copy of M).
>>> hash(A) #random
12
>>> v = {A:Integer(1)}; v
{[10  1]
 [ 2  3]: 1}

A.set_immutable()
A.is_mutable()
A[0,0] = 10
hash(A) #random
v = {A:1}; v
set_row_to_multiple_of_row(i, j, s)[source]

Set row i equal to s times row j.

EXAMPLES: We change the second row to -3 times the first row:

sage: a = matrix(ZZ, 2, 3, range(6)); a
[0 1 2]
[3 4 5]
sage: a.set_row_to_multiple_of_row(1, 0, -3)
sage: a
[ 0  1  2]
[ 0 -3 -6]

>>> from sage.all import *
>>> a = matrix(ZZ, Integer(2), Integer(3), range(Integer(6))); a
[0 1 2]
[3 4 5]
>>> a.set_row_to_multiple_of_row(Integer(1), Integer(0), -Integer(3))
>>> a
[ 0  1  2]
[ 0 -3 -6]

a = matrix(ZZ, 2, 3, range(6)); a
a.set_row_to_multiple_of_row(1, 0, -3)
a

If we try to multiply a row by a rational number, we get an error message:

sage: a.set_row_to_multiple_of_row(1, 0, 1/2)
Traceback (most recent call last):
...
TypeError: Multiplying row by Rational Field element cannot be done over
Integer Ring, use change_ring or with_row_set_to_multiple_of_row instead.

>>> from sage.all import *
>>> a.set_row_to_multiple_of_row(Integer(1), Integer(0), Integer(1)/Integer(2))
Traceback (most recent call last):
...
TypeError: Multiplying row by Rational Field element cannot be done over
Integer Ring, use change_ring or with_row_set_to_multiple_of_row instead.

a.set_row_to_multiple_of_row(1, 0, 1/2)
str(rep_mapping=None, zero=None, plus_one=None, minus_one=None, unicode=False, shape=None, character_art=False, left_border=None, right_border=None, top_border=None, bottom_border=None)[source]

Return a nice string representation of the matrix.

INPUT:

  • rep_mapping – dictionary or callable used to override the usual representation of elements

    If rep_mapping is a dictionary then keys should be elements of the base ring and values the desired string representation. Values sent in via the other keyword arguments will override values in the dictionary. Use of a dictionary can potentially take a very long time due to the need to hash entries of the matrix. Matrices with entries from QQbar are one example.

    If rep_mapping is callable then it will be called with elements of the matrix and must return a string. Simply call repr() on elements which should have the default representation.

  • zero – string (default: None); if not None use the value of zero as the representation of the zero element.

  • plus_one – string (default: None); if not None use the value of plus_one as the representation of the one element.

  • minus_one – string (default: None); if not None use the value of minus_one as the representation of the negative of the one element.

  • unicode – boolean (default: False); whether to use Unicode symbols instead of ASCII symbols for brackets and subdivision lines

  • shape – one of 'square' or 'round' (default: None). Switches between round and square brackets. The default depends on the setting of the unicode keyword argument. For Unicode symbols, the default is round brackets in accordance with the TeX rendering, while the ASCII rendering defaults to square brackets.

  • character_art – boolean (default: False); if True, the result will be of type AsciiArt or UnicodeArt which support line breaking of wide matrices that exceed the window width

  • left_border, right_border – sequence (default: None); if not None, call str() on the elements and use the results as labels for the rows of the matrix. The labels appear outside of the parentheses.

  • top_border, bottom_border – sequence (default: None); if not None, call str() on the elements and use the results as labels for the columns of the matrix. The labels appear outside of the parentheses.

EXAMPLES:

sage: R = PolynomialRing(QQ,6,'z')
sage: a = matrix(2,3, R.gens())
sage: a.__repr__()
'[z0 z1 z2]\n[z3 z4 z5]'

sage: M = matrix([[1,0],[2,-1]])
sage: M.str()
'[ 1  0]\n[ 2 -1]'
sage: M.str(plus_one='+',minus_one='-',zero='.')
'[+ .]\n[2 -]'
sage: M.str({1:"not this one",2:"II"},minus_one='*',plus_one='I')
'[ I  0]\n[II  *]'

sage: def print_entry(x):
....:   if x>0:
....:       return '+'
....:   elif x<0:
....:       return '-'
....:   else: return '.'
...
sage: M.str(print_entry)
'[+ .]\n[+ -]'
sage: M.str(repr)
'[ 1  0]\n[ 2 -1]'

sage: M = matrix([[1,2,3],[4,5,6],[7,8,9]])
sage: M.subdivide(None, 2)
sage: print(M.str(unicode=True))
⎛1 2│3⎞
⎜4 5│6⎟
⎝7 8│9⎠
sage: M.subdivide([0,1,1,3], [0,2,3,3])
sage: print(M.str(unicode=True, shape='square'))
⎡┼───┼─┼┼⎤
⎢│1 2│3││⎥
⎢┼───┼─┼┼⎥
⎢┼───┼─┼┼⎥
⎢│4 5│6││⎥
⎢│7 8│9││⎥
⎣┼───┼─┼┼⎦

>>> from sage.all import *
>>> R = PolynomialRing(QQ,Integer(6),'z')
>>> a = matrix(Integer(2),Integer(3), R.gens())
>>> a.__repr__()
'[z0 z1 z2]\n[z3 z4 z5]'

>>> M = matrix([[Integer(1),Integer(0)],[Integer(2),-Integer(1)]])
>>> M.str()
'[ 1  0]\n[ 2 -1]'
>>> M.str(plus_one='+',minus_one='-',zero='.')
'[+ .]\n[2 -]'
>>> M.str({Integer(1):"not this one",Integer(2):"II"},minus_one='*',plus_one='I')
'[ I  0]\n[II  *]'

>>> def print_entry(x):
...   if x>Integer(0):
...       return '+'
...   elif x<Integer(0):
...       return '-'
...   else: return '.'
...
>>> M.str(print_entry)
'[+ .]\n[+ -]'
>>> M.str(repr)
'[ 1  0]\n[ 2 -1]'

>>> M = matrix([[Integer(1),Integer(2),Integer(3)],[Integer(4),Integer(5),Integer(6)],[Integer(7),Integer(8),Integer(9)]])
>>> M.subdivide(None, Integer(2))
>>> print(M.str(unicode=True))
⎛1 2│3⎞
⎜4 5│6⎟
⎝7 8│9⎠
>>> M.subdivide([Integer(0),Integer(1),Integer(1),Integer(3)], [Integer(0),Integer(2),Integer(3),Integer(3)])
>>> print(M.str(unicode=True, shape='square'))
⎡┼───┼─┼┼⎤
⎢│1 2│3││⎥
⎢┼───┼─┼┼⎥
⎢┼───┼─┼┼⎥
⎢│4 5│6││⎥
⎢│7 8│9││⎥
⎣┼───┼─┼┼⎦

R = PolynomialRing(QQ,6,'z')
a = matrix(2,3, R.gens())
a.__repr__()
M = matrix([[1,0],[2,-1]])
M.str()
M.str(plus_one='+',minus_one='-',zero='.')
M.str({1:"not this one",2:"II"},minus_one='*',plus_one='I')
def print_entry(x):
  if x>0:
      return '+'
  elif x<0:
      return '-'
  else: return '.'
M.str(print_entry)
M.str(repr)
M = matrix([[1,2,3],[4,5,6],[7,8,9]])
M.subdivide(None, 2)
print(M.str(unicode=True))
M.subdivide([0,1,1,3], [0,2,3,3])
print(M.str(unicode=True, shape='square'))

If character_art is set, the lines of large matrices are wrapped in a readable way:

sage: set_random_seed(0)
sage: matrix.random(RDF, 3, 5).str(unicode=True, character_art=True)
⎛ -0.27440062056807446    0.5031965950979831 -0.001975438590219314
⎜ -0.05461130074681608 -0.033673314214051286   -0.9401270875197381
⎝  0.19906256610645512    0.3242250183948632    0.6026443545751128

   -0.9467802263760512    0.5056889961514748⎞
  -0.35104242112828943    0.5084492941557279⎟
   -0.9541798283979341   -0.8948790563276592⎠

>>> from sage.all import *
>>> set_random_seed(Integer(0))
>>> matrix.random(RDF, Integer(3), Integer(5)).str(unicode=True, character_art=True)
⎛ -0.27440062056807446    0.5031965950979831 -0.001975438590219314
⎜ -0.05461130074681608 -0.033673314214051286   -0.9401270875197381
⎝  0.19906256610645512    0.3242250183948632    0.6026443545751128
<BLANKLINE>
   -0.9467802263760512    0.5056889961514748⎞
  -0.35104242112828943    0.5084492941557279⎟
   -0.9541798283979341   -0.8948790563276592⎠

set_random_seed(0)
matrix.random(RDF, 3, 5).str(unicode=True, character_art=True)

The number of floating point digits to display is controlled by matrix.options.precision and can also be set by the IPython magic %precision. This does not affect the internal precision of the represented data, but only the textual display of matrices:

sage: matrix.options.precision = 4
sage: A = matrix(RR, [[1/3, 200/3], [-3, 1e6]]); A
[  0.3333    66.67]
[  -3.000 1.000E+6]
sage: unicode_art(A)
⎛  0.3333    66.67⎞
⎝  -3.000 1.000E+6⎠
sage: matrix.options.precision = None
sage: A
[ 0.333333333333333   66.6666666666667]
[ -3.00000000000000 1.00000000000000e6]

>>> from sage.all import *
>>> matrix.options.precision = Integer(4)
>>> A = matrix(RR, [[Integer(1)/Integer(3), Integer(200)/Integer(3)], [-Integer(3), RealNumber('1e6')]]); A
[  0.3333    66.67]
[  -3.000 1.000E+6]
>>> unicode_art(A)
⎛  0.3333    66.67⎞
⎝  -3.000 1.000E+6⎠
>>> matrix.options.precision = None
>>> A
[ 0.333333333333333   66.6666666666667]
[ -3.00000000000000 1.00000000000000e6]

matrix.options.precision = 4
A = matrix(RR, [[1/3, 200/3], [-3, 1e6]]); A
unicode_art(A)
matrix.options.precision = None
A

Matrices with borders:

sage: M = matrix([[1,2,3], [4,5,6], [7,8,9]])
sage: M.subdivide(None, 2)
sage: print(M.str(unicode=True,
....:             top_border=['ab', 'cde', 'f'],
....:             bottom_border=['*', '', ''],
....:             left_border=[1, 10, 100],
....:             right_border=['', ' <', '']))
     ab cde   f
  1⎛  1   2│  3⎞
 10⎜  4   5│  6⎟ <
100⎝  7   8│  9⎠
      *

>>> from sage.all import *
>>> M = matrix([[Integer(1),Integer(2),Integer(3)], [Integer(4),Integer(5),Integer(6)], [Integer(7),Integer(8),Integer(9)]])
>>> M.subdivide(None, Integer(2))
>>> print(M.str(unicode=True,
...             top_border=['ab', 'cde', 'f'],
...             bottom_border=['*', '', ''],
...             left_border=[Integer(1), Integer(10), Integer(100)],
...             right_border=['', ' <', '']))
     ab cde   f
  1⎛  1   2│  3⎞
 10⎜  4   5│  6⎟ <
100⎝  7   8│  9⎠
      *

M = matrix([[1,2,3], [4,5,6], [7,8,9]])
M.subdivide(None, 2)
print(M.str(unicode=True,
            top_border=['ab', 'cde', 'f'],
            bottom_border=['*', '', ''],
            left_border=[1, 10, 100],
            right_border=['', ' <', '']))
swap_columns(c1, c2)[source]

Swap columns c1 and c2 of self.

EXAMPLES: We create a rational matrix:

sage: M = MatrixSpace(QQ,3,3)
sage: A = M([1,9,-7,4/5,4,3,6,4,3])
sage: A
[  1   9  -7]
[4/5   4   3]
[  6   4   3]

>>> from sage.all import *
>>> M = MatrixSpace(QQ,Integer(3),Integer(3))
>>> A = M([Integer(1),Integer(9),-Integer(7),Integer(4)/Integer(5),Integer(4),Integer(3),Integer(6),Integer(4),Integer(3)])
>>> A
[  1   9  -7]
[4/5   4   3]
[  6   4   3]

M = MatrixSpace(QQ,3,3)
A = M([1,9,-7,4/5,4,3,6,4,3])
A

Since the first column is numbered zero, this swaps the second and third columns:

sage: A.swap_columns(1,2); A
[  1  -7   9]
[4/5   3   4]
[  6   3   4]

>>> from sage.all import *
>>> A.swap_columns(Integer(1),Integer(2)); A
[  1  -7   9]
[4/5   3   4]
[  6   3   4]

A.swap_columns(1,2); A
swap_rows(r1, r2)[source]

Swap rows r1 and r2 of self.

EXAMPLES: We create a rational matrix:

sage: M = MatrixSpace(QQ, 3, 3)
sage: A = M([1,9,-7, 4/5,4,3, 6,4,3])
sage: A
[  1   9  -7]
[4/5   4   3]
[  6   4   3]

>>> from sage.all import *
>>> M = MatrixSpace(QQ, Integer(3), Integer(3))
>>> A = M([Integer(1),Integer(9),-Integer(7), Integer(4)/Integer(5),Integer(4),Integer(3), Integer(6),Integer(4),Integer(3)])
>>> A
[  1   9  -7]
[4/5   4   3]
[  6   4   3]

M = MatrixSpace(QQ, 3, 3)
A = M([1,9,-7, 4/5,4,3, 6,4,3])
A

Since the first row is numbered zero, this swaps the first and third rows:

sage: A.swap_rows(0, 2); A
[  6   4   3]
[4/5   4   3]
[  1   9  -7]

>>> from sage.all import *
>>> A.swap_rows(Integer(0), Integer(2)); A
[  6   4   3]
[4/5   4   3]
[  1   9  -7]

A.swap_rows(0, 2); A
with_added_multiple_of_column(i, j, s, start_row=0)[source]

Add s times column j to column i, returning new matrix.

EXAMPLES: We add -1 times the third column to the second column of an integer matrix, remembering to start numbering cols at zero:

sage: a = matrix(ZZ, 2, 3, range(6)); a
[0 1 2]
[3 4 5]
sage: b = a.with_added_multiple_of_column(1, 2, -1); b
[ 0 -1  2]
[ 3 -1  5]

>>> from sage.all import *
>>> a = matrix(ZZ, Integer(2), Integer(3), range(Integer(6))); a
[0 1 2]
[3 4 5]
>>> b = a.with_added_multiple_of_column(Integer(1), Integer(2), -Integer(1)); b
[ 0 -1  2]
[ 3 -1  5]

a = matrix(ZZ, 2, 3, range(6)); a
b = a.with_added_multiple_of_column(1, 2, -1); b

The original matrix is unchanged:

sage: a
[0 1 2]
[3 4 5]

>>> from sage.all import *
>>> a
[0 1 2]
[3 4 5]

a

Adding a rational multiple is okay, and reassigning a variable is okay:

sage: a = a.with_added_multiple_of_column(0, 1, 1/3); a
[ 1/3    1    2]
[13/3    4    5]

>>> from sage.all import *
>>> a = a.with_added_multiple_of_column(Integer(0), Integer(1), Integer(1)/Integer(3)); a
[ 1/3    1    2]
[13/3    4    5]

a = a.with_added_multiple_of_column(0, 1, 1/3); a
with_added_multiple_of_row(i, j, s, start_col=0)[source]

Add s times row j to row i, returning new matrix.

EXAMPLES: We add -3 times the first row to the second row of an integer matrix, remembering to start numbering rows at zero:

sage: a = matrix(ZZ,2,3,range(6)); a
[0 1 2]
[3 4 5]
sage: b = a.with_added_multiple_of_row(1,0,-3); b
[ 0  1  2]
[ 3  1 -1]

>>> from sage.all import *
>>> a = matrix(ZZ,Integer(2),Integer(3),range(Integer(6))); a
[0 1 2]
[3 4 5]
>>> b = a.with_added_multiple_of_row(Integer(1),Integer(0),-Integer(3)); b
[ 0  1  2]
[ 3  1 -1]

a = matrix(ZZ,2,3,range(6)); a
b = a.with_added_multiple_of_row(1,0,-3); b

The original matrix is unchanged:

sage: a
[0 1 2]
[3 4 5]

>>> from sage.all import *
>>> a
[0 1 2]
[3 4 5]

a

Adding a rational multiple is okay, and reassigning a variable is okay:

sage: a = a.with_added_multiple_of_row(0,1,1/3); a
[   1  7/3 11/3]
[   3    4    5]

>>> from sage.all import *
>>> a = a.with_added_multiple_of_row(Integer(0),Integer(1),Integer(1)/Integer(3)); a
[   1  7/3 11/3]
[   3    4    5]

a = a.with_added_multiple_of_row(0,1,1/3); a
with_col_set_to_multiple_of_col(i, j, s)[source]

Set column i equal to s times column j, returning a new matrix.

EXAMPLES: We change the second column to -3 times the first column.

sage: a = matrix(ZZ, 2, 3, range(6)); a
[0 1 2]
[3 4 5]
sage: b = a.with_col_set_to_multiple_of_col(1, 0, -3); b
[ 0  0  2]
[ 3 -9  5]

>>> from sage.all import *
>>> a = matrix(ZZ, Integer(2), Integer(3), range(Integer(6))); a
[0 1 2]
[3 4 5]
>>> b = a.with_col_set_to_multiple_of_col(Integer(1), Integer(0), -Integer(3)); b
[ 0  0  2]
[ 3 -9  5]

a = matrix(ZZ, 2, 3, range(6)); a
b = a.with_col_set_to_multiple_of_col(1, 0, -3); b

Note that the original matrix is unchanged:

sage: a
[0 1 2]
[3 4 5]

>>> from sage.all import *
>>> a
[0 1 2]
[3 4 5]

a

Adding a rational multiple is okay, and reassigning a variable is okay:

sage: a = a.with_col_set_to_multiple_of_col(1, 0, 1/2); a
[  0   0   2]
[  3 3/2   5]

>>> from sage.all import *
>>> a = a.with_col_set_to_multiple_of_col(Integer(1), Integer(0), Integer(1)/Integer(2)); a
[  0   0   2]
[  3 3/2   5]

a = a.with_col_set_to_multiple_of_col(1, 0, 1/2); a
with_permuted_columns(permutation)[source]

Return the matrix obtained from permuting the columns of self by applying the permutation group element permutation.

As permutation group elements act on integers \(\{1,\dots,n\}\), columns are considered numbered from 1 for this operation.

INPUT:

  • permutation – a PermutationGroupElement

OUTPUT: a matrix

EXAMPLES: We create some matrix:

sage: M = matrix(ZZ, [[1,0,0,0,0],[0,2,0,0,0],[0,0,3,0,0],[0,0,0,4,0],[0,0,0,0,5]])
sage: M
[1 0 0 0 0]
[0 2 0 0 0]
[0 0 3 0 0]
[0 0 0 4 0]
[0 0 0 0 5]

>>> from sage.all import *
>>> M = matrix(ZZ, [[Integer(1),Integer(0),Integer(0),Integer(0),Integer(0)],[Integer(0),Integer(2),Integer(0),Integer(0),Integer(0)],[Integer(0),Integer(0),Integer(3),Integer(0),Integer(0)],[Integer(0),Integer(0),Integer(0),Integer(4),Integer(0)],[Integer(0),Integer(0),Integer(0),Integer(0),Integer(5)]])
>>> M
[1 0 0 0 0]
[0 2 0 0 0]
[0 0 3 0 0]
[0 0 0 4 0]
[0 0 0 0 5]

M = matrix(ZZ, [[1,0,0,0,0],[0,2,0,0,0],[0,0,3,0,0],[0,0,0,4,0],[0,0,0,0,5]])
M

Next of all, create a permutation group element and act on M:

sage: # needs sage.groups
sage: G = PermutationGroup(['(1,2,3)(4,5)', '(1,2,3,4,5)'])
sage: sigma, tau = G.gens()
sage: sigma
(1,2,3)(4,5)
sage: M.with_permuted_columns(sigma)
[0 0 1 0 0]
[2 0 0 0 0]
[0 3 0 0 0]
[0 0 0 0 4]
[0 0 0 5 0]

>>> from sage.all import *
>>> # needs sage.groups
>>> G = PermutationGroup(['(1,2,3)(4,5)', '(1,2,3,4,5)'])
>>> sigma, tau = G.gens()
>>> sigma
(1,2,3)(4,5)
>>> M.with_permuted_columns(sigma)
[0 0 1 0 0]
[2 0 0 0 0]
[0 3 0 0 0]
[0 0 0 0 4]
[0 0 0 5 0]

# needs sage.groups
G = PermutationGroup(['(1,2,3)(4,5)', '(1,2,3,4,5)'])
sigma, tau = G.gens()
sigma
M.with_permuted_columns(sigma)
with_permuted_rows(permutation)[source]

Return the matrix obtained from permuting the rows of self by applying the permutation group element permutation.

As permutation group elements act on integers \(\{1,\dots,n\}\), rows are considered numbered from 1 for this operation.

INPUT:

  • permutation – a PermutationGroupElement

OUTPUT: a matrix

EXAMPLES: We create a matrix:

sage: M = matrix(ZZ, [[1,0,0,0,0],[0,2,0,0,0],[0,0,3,0,0],[0,0,0,4,0],[0,0,0,0,5]])
sage: M
[1 0 0 0 0]
[0 2 0 0 0]
[0 0 3 0 0]
[0 0 0 4 0]
[0 0 0 0 5]

>>> from sage.all import *
>>> M = matrix(ZZ, [[Integer(1),Integer(0),Integer(0),Integer(0),Integer(0)],[Integer(0),Integer(2),Integer(0),Integer(0),Integer(0)],[Integer(0),Integer(0),Integer(3),Integer(0),Integer(0)],[Integer(0),Integer(0),Integer(0),Integer(4),Integer(0)],[Integer(0),Integer(0),Integer(0),Integer(0),Integer(5)]])
>>> M
[1 0 0 0 0]
[0 2 0 0 0]
[0 0 3 0 0]
[0 0 0 4 0]
[0 0 0 0 5]

M = matrix(ZZ, [[1,0,0,0,0],[0,2,0,0,0],[0,0,3,0,0],[0,0,0,4,0],[0,0,0,0,5]])
M

Next of all, create a permutation group element and act on M:

sage: # needs sage.groups
sage: G = PermutationGroup(['(1,2,3)(4,5)', '(1,2,3,4,5)'])
sage: sigma, tau = G.gens()
sage: sigma
(1,2,3)(4,5)
sage: M.with_permuted_rows(sigma)
[0 2 0 0 0]
[0 0 3 0 0]
[1 0 0 0 0]
[0 0 0 0 5]
[0 0 0 4 0]

>>> from sage.all import *
>>> # needs sage.groups
>>> G = PermutationGroup(['(1,2,3)(4,5)', '(1,2,3,4,5)'])
>>> sigma, tau = G.gens()
>>> sigma
(1,2,3)(4,5)
>>> M.with_permuted_rows(sigma)
[0 2 0 0 0]
[0 0 3 0 0]
[1 0 0 0 0]
[0 0 0 0 5]
[0 0 0 4 0]

# needs sage.groups
G = PermutationGroup(['(1,2,3)(4,5)', '(1,2,3,4,5)'])
sigma, tau = G.gens()
sigma
M.with_permuted_rows(sigma)
with_permuted_rows_and_columns(row_permutation, column_permutation)[source]

Return the matrix obtained from permuting the rows and columns of self by applying the permutation group elements row_permutation and column_permutation.

As permutation group elements act on integers \(\{1,\dots,n\}\), rows and columns are considered numbered from 1 for this operation.

INPUT:

  • row_permutation – a PermutationGroupElement

  • column_permutation – a PermutationGroupElement

OUTPUT: a matrix

EXAMPLES: We create a matrix:

sage: M = matrix(ZZ, [[1,0,0,0,0],[0,2,0,0,0],[0,0,3,0,0],[0,0,0,4,0],[0,0,0,0,5]])
sage: M
[1 0 0 0 0]
[0 2 0 0 0]
[0 0 3 0 0]
[0 0 0 4 0]
[0 0 0 0 5]

>>> from sage.all import *
>>> M = matrix(ZZ, [[Integer(1),Integer(0),Integer(0),Integer(0),Integer(0)],[Integer(0),Integer(2),Integer(0),Integer(0),Integer(0)],[Integer(0),Integer(0),Integer(3),Integer(0),Integer(0)],[Integer(0),Integer(0),Integer(0),Integer(4),Integer(0)],[Integer(0),Integer(0),Integer(0),Integer(0),Integer(5)]])
>>> M
[1 0 0 0 0]
[0 2 0 0 0]
[0 0 3 0 0]
[0 0 0 4 0]
[0 0 0 0 5]

M = matrix(ZZ, [[1,0,0,0,0],[0,2,0,0,0],[0,0,3,0,0],[0,0,0,4,0],[0,0,0,0,5]])
M

Next of all, create a permutation group element and act on M:

sage: # needs sage.groups
sage: G = PermutationGroup(['(1,2,3)(4,5)', '(1,2,3,4,5)'])
sage: sigma, tau = G.gens()
sage: sigma
(1,2,3)(4,5)
sage: M.with_permuted_rows_and_columns(sigma,tau)
[2 0 0 0 0]
[0 3 0 0 0]
[0 0 0 0 1]
[0 0 0 5 0]
[0 0 4 0 0]

>>> from sage.all import *
>>> # needs sage.groups
>>> G = PermutationGroup(['(1,2,3)(4,5)', '(1,2,3,4,5)'])
>>> sigma, tau = G.gens()
>>> sigma
(1,2,3)(4,5)
>>> M.with_permuted_rows_and_columns(sigma,tau)
[2 0 0 0 0]
[0 3 0 0 0]
[0 0 0 0 1]
[0 0 0 5 0]
[0 0 4 0 0]

# needs sage.groups
G = PermutationGroup(['(1,2,3)(4,5)', '(1,2,3,4,5)'])
sigma, tau = G.gens()
sigma
M.with_permuted_rows_and_columns(sigma,tau)
with_rescaled_col(i, s, start_row=0)[source]

Replaces \(i\)-th col of self by \(s\) times \(i\)-th col of self, returning new matrix.

EXAMPLES: We rescale the last column of a matrix over the integers:

sage: a = matrix(ZZ, 2, 3, range(6)); a
[0 1 2]
[3 4 5]
sage: b = a.with_rescaled_col(2, -2); b
[  0   1  -4]
[  3   4 -10]

>>> from sage.all import *
>>> a = matrix(ZZ, Integer(2), Integer(3), range(Integer(6))); a
[0 1 2]
[3 4 5]
>>> b = a.with_rescaled_col(Integer(2), -Integer(2)); b
[  0   1  -4]
[  3   4 -10]

a = matrix(ZZ, 2, 3, range(6)); a
b = a.with_rescaled_col(2, -2); b

The original matrix is unchanged:

sage: a
[0 1 2]
[3 4 5]

>>> from sage.all import *
>>> a
[0 1 2]
[3 4 5]

a

Adding a rational multiple is okay, and reassigning a variable is okay:

sage: a = a.with_rescaled_col(1, 1/3); a
[  0 1/3   2]
[  3 4/3   5]

>>> from sage.all import *
>>> a = a.with_rescaled_col(Integer(1), Integer(1)/Integer(3)); a
[  0 1/3   2]
[  3 4/3   5]

a = a.with_rescaled_col(1, 1/3); a
with_rescaled_row(i, s, start_col=0)[source]

Replace \(i\)-th row of self by s times \(i\)-th row of self, returning new matrix.

EXAMPLES: We rescale the second row of a matrix over the integers:

sage: a = matrix(ZZ, 3, 2, range(6)); a
[0 1]
[2 3]
[4 5]
sage: b = a.with_rescaled_row(1, -2); b
[ 0  1]
[-4 -6]
[ 4  5]

>>> from sage.all import *
>>> a = matrix(ZZ, Integer(3), Integer(2), range(Integer(6))); a
[0 1]
[2 3]
[4 5]
>>> b = a.with_rescaled_row(Integer(1), -Integer(2)); b
[ 0  1]
[-4 -6]
[ 4  5]

a = matrix(ZZ, 3, 2, range(6)); a
b = a.with_rescaled_row(1, -2); b

The original matrix is unchanged:

sage: a
[0 1]
[2 3]
[4 5]

>>> from sage.all import *
>>> a
[0 1]
[2 3]
[4 5]

a

Adding a rational multiple is okay, and reassigning a variable is okay:

sage: a = a.with_rescaled_row(2, 1/3); a
[  0   1]
[  2   3]
[4/3 5/3]

>>> from sage.all import *
>>> a = a.with_rescaled_row(Integer(2), Integer(1)/Integer(3)); a
[  0   1]
[  2   3]
[4/3 5/3]

a = a.with_rescaled_row(2, 1/3); a
with_row_set_to_multiple_of_row(i, j, s)[source]

Set row i equal to s times row j, returning a new matrix.

EXAMPLES: We change the second row to -3 times the first row:

sage: a = matrix(ZZ, 2, 3, range(6)); a
[0 1 2]
[3 4 5]
sage: b = a.with_row_set_to_multiple_of_row(1, 0, -3); b
[ 0  1  2]
[ 0 -3 -6]

>>> from sage.all import *
>>> a = matrix(ZZ, Integer(2), Integer(3), range(Integer(6))); a
[0 1 2]
[3 4 5]
>>> b = a.with_row_set_to_multiple_of_row(Integer(1), Integer(0), -Integer(3)); b
[ 0  1  2]
[ 0 -3 -6]

a = matrix(ZZ, 2, 3, range(6)); a
b = a.with_row_set_to_multiple_of_row(1, 0, -3); b

Note that the original matrix is unchanged:

sage: a
[0 1 2]
[3 4 5]

>>> from sage.all import *
>>> a
[0 1 2]
[3 4 5]

a

Adding a rational multiple is okay, and reassigning a variable is okay:

sage: a = a.with_row_set_to_multiple_of_row(1, 0, 1/2); a
[  0   1   2]
[  0 1/2   1]

>>> from sage.all import *
>>> a = a.with_row_set_to_multiple_of_row(Integer(1), Integer(0), Integer(1)/Integer(2)); a
[  0   1   2]
[  0 1/2   1]

a = a.with_row_set_to_multiple_of_row(1, 0, 1/2); a
with_swapped_columns(c1, c2)[source]

Swap columns c1 and c2 of self and return a new matrix.

INPUT:

  • c1, c2 – integers specifying columns of self to interchange

OUTPUT:

A new matrix, identical to self except that columns c1 and c2 are swapped.

EXAMPLES:

Remember that columns are numbered starting from zero.

sage: A = matrix(QQ, 4, range(20))
sage: A.with_swapped_columns(1, 2)
[ 0  2  1  3  4]
[ 5  7  6  8  9]
[10 12 11 13 14]
[15 17 16 18 19]

>>> from sage.all import *
>>> A = matrix(QQ, Integer(4), range(Integer(20)))
>>> A.with_swapped_columns(Integer(1), Integer(2))
[ 0  2  1  3  4]
[ 5  7  6  8  9]
[10 12 11 13 14]
[15 17 16 18 19]

A = matrix(QQ, 4, range(20))
A.with_swapped_columns(1, 2)

Trying to swap a column with itself will succeed, but still return a new matrix.

sage: A = matrix(QQ, 4, range(20))
sage: B = A.with_swapped_columns(2, 2)
sage: A == B
True
sage: A is B
False

>>> from sage.all import *
>>> A = matrix(QQ, Integer(4), range(Integer(20)))
>>> B = A.with_swapped_columns(Integer(2), Integer(2))
>>> A == B
True
>>> A is B
False

A = matrix(QQ, 4, range(20))
B = A.with_swapped_columns(2, 2)
A == B
A is B

The column specifications are checked.

sage: A = matrix(4, range(20))
sage: A.with_swapped_columns(-1, 2)
Traceback (most recent call last):
...
IndexError: matrix column index out of range

sage: A.with_swapped_columns(2, 5)
Traceback (most recent call last):
...
IndexError: matrix column index out of range

>>> from sage.all import *
>>> A = matrix(Integer(4), range(Integer(20)))
>>> A.with_swapped_columns(-Integer(1), Integer(2))
Traceback (most recent call last):
...
IndexError: matrix column index out of range

>>> A.with_swapped_columns(Integer(2), Integer(5))
Traceback (most recent call last):
...
IndexError: matrix column index out of range

A = matrix(4, range(20))
A.with_swapped_columns(-1, 2)
A.with_swapped_columns(2, 5)
with_swapped_rows(r1, r2)[source]

Swap rows r1 and r2 of self and return a new matrix.

INPUT:

  • r1, r2 – integers specifying rows of self to interchange

OUTPUT:

A new matrix, identical to self except that rows r1 and r2 are swapped.

EXAMPLES:

Remember that rows are numbered starting from zero.

sage: A = matrix(QQ, 4, range(20))
sage: A.with_swapped_rows(1, 2)
[ 0  1  2  3  4]
[10 11 12 13 14]
[ 5  6  7  8  9]
[15 16 17 18 19]

>>> from sage.all import *
>>> A = matrix(QQ, Integer(4), range(Integer(20)))
>>> A.with_swapped_rows(Integer(1), Integer(2))
[ 0  1  2  3  4]
[10 11 12 13 14]
[ 5  6  7  8  9]
[15 16 17 18 19]

A = matrix(QQ, 4, range(20))
A.with_swapped_rows(1, 2)

Trying to swap a row with itself will succeed, but still return a new matrix.

sage: A = matrix(QQ, 4, range(20))
sage: B = A.with_swapped_rows(2, 2)
sage: A == B
True
sage: A is B
False

>>> from sage.all import *
>>> A = matrix(QQ, Integer(4), range(Integer(20)))
>>> B = A.with_swapped_rows(Integer(2), Integer(2))
>>> A == B
True
>>> A is B
False

A = matrix(QQ, 4, range(20))
B = A.with_swapped_rows(2, 2)
A == B
A is B

The row specifications are checked.

sage: A = matrix(4, range(20))
sage: A.with_swapped_rows(-1, 2)
Traceback (most recent call last):
...
IndexError: matrix row index out of range

sage: A.with_swapped_rows(2, 5)
Traceback (most recent call last):
...
IndexError: matrix row index out of range

>>> from sage.all import *
>>> A = matrix(Integer(4), range(Integer(20)))
>>> A.with_swapped_rows(-Integer(1), Integer(2))
Traceback (most recent call last):
...
IndexError: matrix row index out of range

>>> A.with_swapped_rows(Integer(2), Integer(5))
Traceback (most recent call last):
...
IndexError: matrix row index out of range

A = matrix(4, range(20))
A.with_swapped_rows(-1, 2)
A.with_swapped_rows(2, 5)
sage.matrix.matrix0.set_max_cols(n)[source]

Set the global variable max_cols (which is used in deciding how to output a matrix).

EXAMPLES:

sage: from sage.matrix.matrix0 import set_max_cols
sage: set_max_cols(50)
doctest:...: DeprecationWarning: 'set_max_cols' is replaced by 'matrix.options.max_cols'
See https://github.com/sagemath/sage/issues/30552 for details.

>>> from sage.all import *
>>> from sage.matrix.matrix0 import set_max_cols
>>> set_max_cols(Integer(50))
doctest:...: DeprecationWarning: 'set_max_cols' is replaced by 'matrix.options.max_cols'
See https://github.com/sagemath/sage/issues/30552 for details.

from sage.matrix.matrix0 import set_max_cols
set_max_cols(50)
sage.matrix.matrix0.set_max_rows(n)[source]

Set the global variable max_rows (which is used in deciding how to output a matrix).

EXAMPLES:

sage: from sage.matrix.matrix0 import set_max_rows
sage: set_max_rows(20)
doctest:...: DeprecationWarning: 'set_max_rows' is replaced by 'matrix.options.max_rows'
See https://github.com/sagemath/sage/issues/30552 for details.

>>> from sage.all import *
>>> from sage.matrix.matrix0 import set_max_rows
>>> set_max_rows(Integer(20))
doctest:...: DeprecationWarning: 'set_max_rows' is replaced by 'matrix.options.max_rows'
See https://github.com/sagemath/sage/issues/30552 for details.

from sage.matrix.matrix0 import set_max_rows
set_max_rows(20)
sage.matrix.matrix0.unpickle(cls, parent, immutability, cache, data, version)[source]

Unpickle a matrix. This is only used internally by Sage. Users should never call this function directly.

EXAMPLES: We illustrating saving and loading several different types of matrices.

OVER \(\ZZ\):

sage: A = matrix(ZZ, 2, range(4))
sage: loads(dumps(A))  # indirect doctest
[0 1]
[2 3]

>>> from sage.all import *
>>> A = matrix(ZZ, Integer(2), range(Integer(4)))
>>> loads(dumps(A))  # indirect doctest
[0 1]
[2 3]

A = matrix(ZZ, 2, range(4))
loads(dumps(A))  # indirect doctest

Sparse OVER \(\QQ\):

Dense over \(\QQ[x,y]\):

Dense over finite field.