EIGENVALUE

EIGENVALUE calculates eigenvalues of a symmetric matrix.

Usage

eigenvalue gdxin i a gdxout ev

where

gdxin

name of gdxfile with matrix

i

name of set used in matrix

a

name of 2 dimensional parameter inside gdxin

gdxout

name of gdxfile for results (eigenvalues)

ev

name of 1 dimensional parameter inside gdxout

Calculates eigenvalues of symmetric matrix a(i,j) where i and j are aliased sets.

Example

$ontext

   Eigenvalue example.

octave:1> a=[9 1 1; 1 9 1; 1 1 9]
a =

  9  1  1
  1  9  1
  1  1  9

octave:2> eig(a)
ans =

   8
   8
  11
 
$offtext

set i /i1*i3/;
alias (i,j);

table a(i,j)
      i1   i2   i3
i1     9    1    1
i2     1    9    1
i3     1    1    9
 
;

parameter e(i) 'eigenvalues';
 
execute_unload 'mat.gdx',i,a;
execute '=eigenvalue.exe mat.gdx i a ev.gdx e';
execute_load 'ev.gdx',e;

display a,e;