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Re: manipulating sparse matrices
From: |
Andy Adler |
Subject: |
Re: manipulating sparse matrices |
Date: |
Fri, 14 Oct 2005 21:26:12 -0400 (EDT) |
On Fri, 14 Oct 2005, Mike Miller wrote:
> I'm using Octave 2.1.71 on Linux with Octave-Forge 2005.06.13.
>
> I have two questions about sparse matrices...
>
> If I do this...
>
> a = speye(1000);
> a(1,1) = 2;
>
> ...the resulting 'a' matrix is no longer of class "sparse" and it takes up
> 8 MB of RAM. That's not good for me. Is there a way to reassign an
> element of a sparse matrix without changing its class? I believe this
> just works in 2.9, but is there a way to do it in 2.1.71?
That is correct. The sparse code in octave-forge does not support
assignment. David Bateman has stated that his need for this feature
was the primary motivator for writing the new sparse code in 2.9.x.
--
Andy Adler <address@hidden> 1(613)562-5800x6218
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