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Re: Is A\b using a sparse solver if A is sparse?
From: |
LUK ShunTim |
Subject: |
Re: Is A\b using a sparse solver if A is sparse? |
Date: |
Thu, 02 Feb 2006 13:16:09 +0800 |
User-agent: |
Debian Thunderbird 1.0.7 (X11/20051017) |
Geordie McBain wrote:
> 2.1.x doesn't have the new sparse implementation; it's only in 2.9.x.
> For 2.9, the sparse implementation is in Octave proper rather than
> Octave Forge.
>
> There is a debian package for octave2.9.
yes, thanks. But still similar result. :-(
<diary>
octave2.9:3> A=sprand(2500,2500,0.03);
octave2.9:4> b=eye(2500,1);
octave2.9:5> r=A*b;
octave2.9:6> fullA=full(A);
octave2.9:7> tic;A\r;toc
ans = 25.196
octave2.9:8> tic;A\r;toc
ans = 12.622
octave2.9:9> tic;A\r;toc
ans = 14.420
octave2.9:10> tic;A\r;toc
ans = 12.125
octave2.9:11> tic;A\r;toc
ans = 12.117
octave2.9:12> tic;fullA\r;toc
ans = 6.6568
octave2.9:13> tic;fullA\r;toc
ans = 5.1657
octave2.9:14> tic;fullA\r;toc
ans = 5.1253
octave2.9:15> tic;fullA\r;toc
ans = 5.1157
</diary>
Regards,
ST
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Re: Is A\b using a sparse solver if A is sparse?, David Bateman, 2006/02/02