[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[Octave-bug-tracker] [bug #45890] Sparse A*x and A+B are a bit slow

From: Marco Caliari
Subject: [Octave-bug-tracker] [bug #45890] Sparse A*x and A+B are a bit slow
Date: Thu, 16 Aug 2018 16:10:24 -0400 (EDT)
User-agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:61.0) Gecko/20100101 Firefox/61.0

Follow-up Comment #20, bug #45890 (project octave):

Just few comments. 
The matrix A has not exactly NNZ nonzeros (because of repeated entries in the
pattern). This may explain some differences. 
In the sum A+B, A and B have the same sparsity pattern. Does octave check for
that and specialize the code? Maybe matlab does it. In finite difference or
element discretizations it is quite natural to sum up matrices with the same
sparsity pattern. I would be in favor of such a specialization, if not already
@Dmitri: in the sparse A*x and A'*x no BLAS is used, just two nested for


Reply to this item at:


  Message sent via Savannah

reply via email to

[Prev in Thread] Current Thread [Next in Thread]