INVERT inverts a matrix.

Attention

INVERT is deprecated (see GAMS 36 Cholesky, Eigenvalue, Eigenvector, Invert release notes). Please use $libInclude linalg Invert instead.

Usage

invert gdxin i a gdxout inva

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 (inverse matrix)

inva

name of 2 dimensional parameter inside gdxout

Calculates the inverse of a matrix a(i,j), where i and j are aliased sets. The matrix inva in gdxout will contain the inverse.

Example

$onText
Finds the inverse of a matrix through an external program.

Erwin Kalvelagen, march 2005

Reference: model gauss.gms from the model library
           http://www.gams.com/modlib/libhtml/gauss.htm
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Set i /i1*i3 /;

Alias (i,j);

Table a(i,j) 'original matrix'
        i1   i2   i3
   i1    1    2    3
   i2    1    3    4
   i3    1    4    3;

Parameter inva(i,j) 'inverse of a';

execute_unload 'a.gdx', i, a;
execute '=invert.exe a.gdx i a b.gdx inva';
execute_load 'b.gdx', inva;

display a, inva;