1#!/usr/bin/perl -w
2use Math::GSL::Matrix;
3use strict;
4my $matrix = Math::GSL::Matrix->new(2,2)
5                              ->set_row(0, [0,-1] )
6                              ->set_row(1, [1, 0] );
7print <<STUFF;
8Finding eigenvalue/eigenvectors for
9[ 0  -1 ]
10[ 1   0 ]
11STUFF
12
13# this actually calculates the eigenvalues and eigenvectors and returns
14# an array reference of eigenvalues (scalars which may be Math::Complex objects)
15# and an array reference of Math::GSL::VectorComplex objects
16my ($eigenvalues, $eigenvectors) = $matrix->eigenpair;
17my ($eig1,$eig2) = @$eigenvalues;
18my ($u,$v)       = @$eigenvectors;
19my ($u1,$u2)     = $u->as_list;
20my ($v1,$v2)     = $v->as_list;
21
22print <<ANSWER;
23
24Eigenvectors:
25
26u = ($u1,$u2)
27v = ($v1,$v2)
28
29Eigenvalues:
30
31lambda_0 = $eig1
32lambda_1 = $eig2
33
34ANSWER
35