$title 'test gdxmerge - verify that an aliased set can be merged' (GDXMERG1,SEQ=363)

$onText
In this model we:
   1.  Write a small helper gams file
   2.  Execute this file a few times to generate different gdx files
   3.  call on gdxmerge to merge the gdx files
   4.  read some data back to verify the contents

Contributor: Paul van der Eijk
$offText

$onEcho > helper.gms
set i /i1*i5/;
alias(i,j);
parameter A(i,j);
A(i,j)=10 * Ord(i) + Ord(j) + %base%;
$offEcho

$call gams helper --base=1000 gdx=f1.gdx lo=0
$call gams helper --base=2000 gdx=f2.gdx lo=0
$call gams helper --base=3000 gdx=f3.gdx lo=0
$call gdxmerge f1.gdx f2.gdx f3.gdx > %system.nullfile%

set i /i1*i5/;
alias(i, j);
set m /f1, f2, f3/;
$gdxIn merged.gdx
set mi(m, i);
set mj(m, i);
parameter mA(m, i, j);
*this is fine
$load mA=A
*without update to gdxmerge this load fails
$load mi=i mj=j
$gdxIn

parameter VA(m, i, j);
VA(m, i, j)= 10 * Ord(i) + Ord(j) + Ord(m) * 1000;
VA(m, i, j) = VA(m, i, j) - mA(m, i, j);
Abort$(Card(VA) <> 0) "merged failed";
Abort$(Card(i)*Card(m) <> card(mi)) "card of aliased set is wrong";