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Re: [igraph] matrix times a vector

From: Gábor Csárdi
Subject: Re: [igraph] matrix times a vector
Date: Thu, 2 Jun 2011 10:17:36 -0400


igraph 0.5.x does not have a function for this. You can write it
yourself, or use BLAS/LAPACK. &MATRIX(mat, 0, 0) gives you a pointer
to the first element of the column-wise stored matrix, VECTOR(vec) is
a pointer to the first element of a vector.

igraph 0.6.x has igraph_blas_dgemv() which is a wrapper to the
corresponding BLAS function.


On Wed, Jun 1, 2011 at 10:50 AM, franck kalala <address@hidden> wrote:
> Hey all,
> how to multiply a sqaure matrix (n by n) by a column vector (n by 1)  using
> igrap?
> I am using the c version.
> Cheers
> _______________________________________________
> igraph-help mailing list
> address@hidden
> https://lists.nongnu.org/mailman/listinfo/igraph-help

Gabor Csardi <address@hidden>     MTA KFKI RMKI

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