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## Re: generating sparse matricies

**From**: |
Søren Hauberg |

**Subject**: |
Re: generating sparse matricies |

**Date**: |
Sat, 01 Oct 2005 09:27:15 +0200 |

I can't remember if this works in 2.164, but in 2.9.3 you can just use
'sprand'
/Søren
fre, 30 09 2005 kl. 23:07 -0700, skrev Paul Roberts:
>* Hello,*
>* *
>* I am using Octave 2.1.64. I would like to iteratively build a sparse*
>* matrix uring code like:*
>* *
>* X = sparse(10000,1000);*
>* for j=1:1000*
>* X(:, j) = rand(10000,1) < 0.01;*
>* end*
>* *
>* I have found however that when I try X(:,j) = rand(10000,1) < 0.01;,*
>* the matrix X is converted to a full matrix. This happens even if I*
>* write: X(:,j) = sparse(rand(10000,1) < 0.01); *
>* *
>* My questions are: (1) Will this be changed in future versions of*
>* Octave and (2) is there an efficient work around for this issue? I*
>* have tried using sphcat, but that seems to be very slow.*
>* *
>* Thanks!*
>* *
>* Paul*
>* *
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