Le 30/04/2010 18:54, Robert Bradshaw a écrit :
O

sage: m = matrix(RDF, 5, sparse=True)
sage: type(m)
<type 'sage.matrix.matrix_generic_sparse.Matrix_generic_sparse'>

So it's our completely generic sparse implementation, stored as a
dictionary of non-zero entries.

http://hg.sagemath.org/sage-main/file/e2ccb846f296/sage/matrix/matrix_generic_sparse.pyx#l1


If it is possible for sage to build automatically csc or csr matrices,
then using sparse solvers is trivial. Otherwise I think it is
necessary to build Scipy matrices (lil matrices converted to csr or
csc format).

We don't have support for that, but it would probably be a nice thing to
have.



Ok... may be it is not too complicated to implement: I currently transform C++ maps (i,j)-> value to csr format in my C++ codes; it is a program of 10 lines. I could look at this (when I'll have time to do that).

What would be the best (if possible):
 - a conversion by hand:
    Q=matrix(RDF,100000,sparse=True)
    ....
    A=Q.csr()   or A=csr(Q)
 -or try to make it automatically?
That is to say, when calling a solve method (which will possibly call SuperLu, which needs csr storage) on Q, create the csr storage representation of Q?

Yours

t.



- Robert


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