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## Re: large sparse matrix

**From**: |
Carlo de Falco |

**Subject**: |
Re: large sparse matrix |

**Date**: |
Tue, 1 Sep 2009 10:04:17 +0200 |

2009/9/1 Carlo de Falco <address@hidden>:
>*> Also, what does the code*
>*>*
>*> [R, p, q] = chol(A);*
>*> nnz(R)*
>*>*
>
>*> work for Octave and Matlab?*
>
>* I tried this in Octave, after 30 min it did not finish yet...*
>* I will only be able to try it on Matlab tomorrow.*
>
>*> If so what is the value of NNZ of the factorization in both cases.*
I killed the Octave after it had been running more than one hour and
produced no result.
In Matlab it ran in less than a second and the result was:
>*> [R,p,q]=chol(A);*
>*> nnz (R)*
ans =
1368019
>*> issparse (R)*
ans =
1
>*> nnz(R)/prod(size(A))*
ans =
7.035863106552923e-03
Thanks,
c.