examples/matrix/nonsymmetric_eigen

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