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## Re: Which algorithm does Octave use to invert the following positive sem

**From**: |
Martin Helm |

**Subject**: |
Re: Which algorithm does Octave use to invert the following positive semidefinite matrix? |

**Date**: |
Mon, 4 Apr 2011 18:06:10 +0200 |

**User-agent**: |
KMail/1.13.6 (Linux/2.6.34.7-0.7-desktop; KDE/4.6.1; x86_64; ; ) |

Am Montag, 4. April 2011, 18:05:02 schrieb Martin Helm:
>* Am Montag, 4. April 2011, 17:53:51 schrieb Martin Helm:*
>* > Am Montag, 4. April 2011, 16:45:28 schrieb Olumide:*
>* > > Whereas the LAPACK routines DPOTRI and DGETRI fail because the matrix*
>* > > has zero elements along its diagonal, Octave successfully computes*
>* > > the inverts the matrix to be*
>* *
>* dpotri will of course fail since the matrix violates the conditions (not*
>* positve semidefinite), dgetri should work, BUT did you call degtrf before?*
Typo: should read:
dpotri will of course fail since the matrix violates the conditions (not
positve definite)