[Numpy-discussion] matrix inversion

Nadav Horesh nadavh@visionsense....
Wed Aug 10 23:21:34 CDT 2011


The matrix in singular, so you can not expect a stable inverse.

   Nadav.

________________________________
From: numpy-discussion-bounces@scipy.org [numpy-discussion-bounces@scipy.org] On Behalf Of jp d [yoyoq@yahoo.com]
Sent: 11 August 2011 03:50
To: numpy-discussion@scipy.org
Subject: [Numpy-discussion] matrix inversion

hi,
i am trying to invert matrices like this:
[[ 0.01643777 -0.13539939  0.11946689]
 [ 0.12479926  0.01210898 -0.09217618]
 [-0.13050087  0.07575163  0.01144993]]

in perl using Math::MatrixReal;
and in various online calculators i get
[  2.472715991745  3.680743681735 -3.831392002314 ]
[ -4.673105249083 -5.348238625096 -5.703193038649 ]
[  2.733966489601 -6.567940452290 -5.936617926811 ]

using python , numpy and linalg.inv (or linalg.pinv) i get  a divergent answer
[[  6.79611151e+07   1.01163031e+08   1.05303510e+08]
 [  1.01163057e+08   1.50585545e+08   1.56748838e+08]
 [  1.05303548e+08   1.56748831e+08   1.63164381e+08]]

any suggestions?

thanks
jpd
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