Help On Inverese Matrix

Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

I am new into perl.

I decided to use MatrixReal module to find inverse of a given matrix.

#! /usr/local/bin/perl -w

use strict;
use Math::MatrixReal;

sub INVERT_MATRIX
{
my $matrix =Math::MatrixReal->new_from_string(<<'MATRIX');
[ 0 1 2 ]
[ 3 4 5 ]
[ 6 7 8 ]
MATRIX
print $matrix;
my $inverse = $matrix->decompose_LR->invert_LR ;
print $inverse;
[download]

when I try to print inverese matrix as it was given in the book I get the following output:

 % myprog
[  0.000000000000E+00  1.000000000000E+00  2.000000000000E+00 ]
[  3.000000000000E+00  4.000000000000E+00  5.000000000000E+00 ]
[  6.000000000000E+00  7.000000000000E+00  8.000000000000E+00 ]
Use of uninitialized value in print at myprog line 34.
[download]

can somebody tell me what I did wrong?

by the way I do have a [ and a ] surrounding those numbers properly

this web app won't accept it in that region due to that

Code tags by Ovid

Comment on Help On Inverese Matrix Select or Download Code

Replies are listed 'Best First'.
Re: Help On Inverse Matrix by Ea (Chaplain) on Jul 18, 2001 at 12:53 UTC
This is not the answer you are looking for, but an alternative module for dealing with matrices is the Perl Data Language. The module PDL::Slatec has a function called `matinv` , which is gives the inverse of a square matrix like so, `($inv) = matinv($mat)` (pretty much stolen from the docs) You will probably lose a little time installing and learning how to form the matrix, but if you are regularly involved in Numerical Funny Business, it might be worth it in the long run. The web page is http://pdl.perl.org/ which will explain the module and lead you to a low traffic mailing list with lotsa helpful people.	[reply] [d/l] [select]
Re^2: Help On Inverse Matrix by etj (Deacon) on Jul 08, 2022 at 19:12 UTC
PDL::Slatec uses bundled parts of LINPACK and some of BLAS. To use the more up-to-date LAPACK with PDL, I don't think there's a better option than Greg Vanuxem's PDL::LinearAlgebra, which has an excellent PDL-ish (and in fact quite MATLAB-reminiscent) wrapping interface.	[reply]
Re: Help On Inverese Matrix by no_slogan (Deacon) on Jul 18, 2001 at 02:27 UTC
Your matrix is singular. There is no inverse. Try a different matrix.	[reply]
Re: Help On Inverese Matrix by ariels (Curate) on Jul 18, 2001 at 09:08 UTC
Further to no_slogan's answer, you can see your matrix is singular by noting that (this is algebraic notation, not Perl!) 2*[3,4,5] - [0,1,2] = [6,7,8]	[reply]


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