[SciPy-User] isn't it a bug in scipy.sparse? + some questions
Dmitrey
tmp50@ukr....
Sun Nov 8 05:22:34 CST 2009
Hi scipy.sparse developers and all other scipy users,
I'm trying to take benefits for solving SLEs in FuncDesigner via involving scipy.sparse.
Some examples are here
http://openopt.org/FuncDesignerDoc#Solving_systems_of_linear_equations
and example for sparse SLEs is here
http://trac.openopt.org/openopt/browser/PythonPackages/FuncDesigner/FuncDesigner/examples/sparseSLE.py
It already works faster than using dense matrices, but I want to speedup it even more, so I have some questions and seems like bug report (scipy.__version__ 0.7.0):
from scipy import sparse
from numpy import *
a=sparse.lil_matrix((3,1))
a[0:3,:] = ones(3)
print a.todense()
#prints
[[ 1.]
[ 0.]
[ 0.]]
while I expect all-ones
Questions:
1) Seems like a[some_ind,:]=something works very, very slow for lil. I have implemented a workaround, but can I use a[some_ind,:] for another format than lil? (seems like all other ones doesn't support it).
2) What is current situation with matmat and matvec functions? They say "deprecated" but no alternative is mentioned.
3) What is current situation with scipy.sparse.linalg.spsolve? It says
/usr/lib/python2.6/dist-packages/scipy/sparse/linalg/dsolve/linsolve.py:78: DeprecationWarning: scipy.sparse.linalg.dsolve.umfpack will be removed, install scikits.umfpack instead
' install scikits.umfpack instead', DeprecationWarning )
But I don't want my code to be dependent on a scikits module. Are there another default/autoselect solver for sparse SLEs?
If no, which one would you recommend me to use as default for sparse SLEs - bicg, gmres, something else?
Thank you in advance, D.
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