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Re: How can one get the size of a sparse matrix ?
From: |
David Bateman |
Subject: |
Re: How can one get the size of a sparse matrix ? |
Date: |
Thu, 6 Jan 2005 14:02:34 +0100 |
User-agent: |
Mutt/1.5.6i |
According to Schloegl Alois <address@hidden> (on 01/06/05):
>
>
> I'm using Andy Adlers Sparse toolbox using Octave-forge.
>
> octave:10> which sparse
> sparse is the dynamically-linked function from the file
> /usr/local/libexec/octave/2.1.64/site/oct/i686-pc-linux-gnu/octave-forge/sparse.oct
>
> When I try to obtain number of rows and columns of a sparse matrix, I get
> always
> -1.
>
> octave:11> X = sparse(2:5,1:4,1);
> octave:12> size(X),
> ans =
>
> -1 -1
>
>
> How can one obtain the size of a sparse matrix ?
With Andy's toolbox, I'm not seeing this behavious
octave:1> version
ans = 2.1.64
octave:2> OCTAVE_FORGE_VERSION
ans = 20041116
octave:3> X = sparse(2:5,1:4,1);
octave:4> size(X),
ans =
5 4
Fsize returns rep->dims(), which in the case of Andy's package is the
dim_vector dims (void) const {dim_vector dv (rows(), cols()); return dv; }
which are
int octave_sparse::rows (void) const {
return X.nrow;
}
int octave_sparse::columns (void) const {
return X.ncol;
}
Where X is the SuperLU matrix. Frankly, I can see no reason for this to
fail in the way you show... What seems to be happening for you is that
octave_sparse::dims isn't being used as rep->dims, and the default version
dim_vector octave_base_value::dims (void) const { return dim_vector (-1, -1); }
is being returned... Again, I see no reason for this looking at Andy's code..
Regards
David
--
David Bateman address@hidden
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Parc Les Algorithmes, Commune de St Aubin +33 1 69 35 77 01 (Fax)
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