Sage Reference Manual: Matrices and Spaces of Matrices - Mirrors

Sage Reference Manual: Matrices and Spaces of Matrices, Release 6.1.1
EXAMPLES:
sage: M = matrix(5, 5, range(25))
sage: M.subdivide(3,3); M
[ 0 1 2| 3 4]
[ 5 6 7| 8 9]
[10 11 12|13 14]
[--------+-----]
[15 16 17|18 19]
[20 21 22|23 24]
sage: M.subdivision_entry(0,0,1,2)
7
sage: M.subdivision(0,0)[1,2]
7
sage: M.subdivision_entry(0,1,0,0)
3
sage: M.subdivision_entry(1,0,0,0)
15
sage: M.subdivision_entry(1,1,1,1)
24
Even though this entry exists in the matrix, the index is invalid for the submatrix.
sage: M.subdivision_entry(0,0,4,0)
Traceback (most recent call last):
...
IndexError: Submatrix 0,0 has no entry 4,0
subdivisions()
Returns the current subdivision of self.
EXAMPLES:
sage: M = matrix(5, 5, range(25))
sage: M.subdivisions()
([], [])
sage: M.subdivide(2,3)
sage: M.subdivisions()
([2], [3])
sage: N = M.parent()(1)
sage: N.subdivide(M.subdivisions()); N
[1 0 0|0 0]
[0 1 0|0 0]
[-----+---]
[0 0 1|0 0]
[0 0 0|1 0]
[0 0 0|0 1]
subs(in_dict=None, **kwds)
EXAMPLES:
sage: var(’a,b,d,e’)
(a, b, d, e)
sage: m = matrix([[a,b], [d,e]])
sage: m.substitute(a=1)
[1 b]
[d e]
sage: m.subs(a=b, b=d)
[b d]
[d e]
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