Sage Reference Manual: Matrices and Spaces of Matrices - Mirrors

Sage Reference Manual: Matrices and Spaces of Matrices, Release 6.1.1
is_sparse()
Returns True if matrices in self are sparse and False otherwise.
EXAMPLES:
sage: Mat(GF(2011),10000).is_sparse()
False
sage: Mat(GF(2011),10000,sparse=True).is_sparse()
True
matrix(x=0, coerce=True, copy=True, rows=None)
Create a matrix in self.
INPUT:
•x – (default: 0) data to construct a new matrix from. Can be one of the following:
–0, corresponding to the zero matrix;
–1, corresponding to the identity_matrix;
–a matrix, whose dimensions must match self and whose base ring must be convertible to the
base ring of self;
–a list of entries corresponding to all elements of the new matrix;
–a list of rows with each row given as an iterable;
•coerce – (default: True) whether to coerce x into self;
•copy – (default: True) whether to copy x during construction (makes a difference only if x is a
matrix in self).
OUTPUT:
•a matrix in self.
EXAMPLES:
sage: M = MatrixSpace(ZZ, 2)
sage: M.matrix([[1,0],[0,-1]])
[ 1 0]
[ 0 -1]
sage: M.matrix([1,0,0,-1])
[ 1 0]
[ 0 -1]
sage: M.matrix([1,2,3,4])
[1 2]
[3 4]
sage: M.matrix([1,2,3,4],rows=False)
doctest:...: DeprecationWarning:
’rows=True/False’ parameter is deprecated!
See http://trac.sagemath.org/13012 for details.
[1 3]
[2 4]
Note that the last “flip” cannot be performed if x is a matrix, no matter what is rows (it used to be possible
but was fixed by Trac 10793):
sage: projection = matrix(ZZ,[[1,0,0],[0,1,0]])
sage: projection
[1 0 0]
[0 1 0]
sage: projection.parent()
8 Chapter 1. Matrix Spaces