On Oct 23, 12:20 pm, Simon King <simon.k...@nuigalway.ie> wrote:
> Hi!
>
> On 23 Okt., 11:59, Simon King <simon.k...@nuigalway.ie> wrote:
>
> > So, one should create an empty matrix and then insert the elements row
> > by row.
>
> It it also more efficient on a smaller skale (and does the right
> thing):
>
> sage: MS = MatrixSpace(ZZ,100,50)
> sage: L = [[ZZ.random_element() for _ in range(50)] for __ in
> range(100)]
> sage: timeit('M = MS(0)\nfor i in range(len(L)): M[i]=L[i]')
> 625 loops, best of 3: 602 µs per loop
> sage: timeit('M = Matrix(ZZ,L)')
> 125 loops, best of 3: 2.81 ms per loop
> sage: M = MS(0)
> sage: for i in range(len(L)): M[i]=L[i]
> ....:
> sage: M == Matrix(ZZ,L)
> True
>
> Cheers,
> SimonIn the matrix constructor (matrix in sage/matrix/constructor.py): entries = sum([list(v) for v in args[0]], []) <--- this is bad (quadratic in the length of argv[0] which is the number of rows here) Yann -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org
