invert01.gms : Test invert utility
Test the invert utility:
1. write a square matrix to a GDX file
2. call 'invert' (an external program) to do the inversion
3. read in the invert from a second GDX file
4. test that A * A-inv = I
Contributor: Erwin Kalvelagen and Steve Dirkse, July 2008.
Small Model of Type: GAMS
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$title 'Test invert utility' (INVERT01,SEQ=391)
$ontext
Test the invert utility:
1. write a square matrix to a GDX file
2. call 'invert' (an external program) to do the inversion
3. read in the invert from a second GDX file
4. test that A * A-inv = I
Contributor: Erwin Kalvelagen and Steve Dirkse, July 2008.
$offtext
set i /i1*i3 /;
alias (i,j,k);
table a(i,j) 'original matrix'
i1 i2 i3
i1 1 2 3
i2 1 3 4
i3 1 4 3
;
scalar rc;
parameter
inva(i,j) 'inverse of a'
chk(i,j) 'check the product a * inva'
;
execute_unload 'a.gdx',i,a;
execute 'invert a.gdx i a b.gdx inva >invert.log';
rc=errorlevel;
abort$(rc > 0) 'Nonzero return code from invert', rc;
execute_load 'b.gdx',inva;
rc=errorlevel;
abort$(rc > 0) 'Error loading inverse from b.gdx', rc;
chk(i,j) = sum{k, a(i,k)*inva(k,j)};
chk(i,j) = round(chk(i,j),15);
display a,inva,chk;
chk(i,i) = chk(i,i) - 1;
abort$[card(chk)] 'a * ainv <> identity';
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