nest2.gms : nested if loop solve test with map

Description

```This test for a problem we encountered with 21.0.
if(...,
loop(...,
solve ..
x(...  );

on the second round we got the wrong data because the
driving loop index got messed up.
```

Small Model of Type : GAMS

Category : GAMS Test library

Main file : nest2.gms

``````\$Title nested if loop solve test with map (NEST2,SEQ=63)
\$Ontext
This test for a problem we encountered with 21.0.
if(...,
loop(...,
solve ..
x(...  );

on the second round we got the wrong data because the
driving loop index got messed up.

\$offtext

Sets
i   canning plants   / seattle, san-diego /
j   markets          / new-york, chicago, topeka / ;

Parameters

a(i)  capacity of plant i in cases
/    seattle     350
san-diego   600  /

b(j)  demand at market j in cases
/    new-york    325
chicago     300
topeka      275  / ;

Table d(i,j)  distance in thousands of miles
new-york       chicago      topeka
seattle          2.5           1.7          1.8
san-diego        2.5           1.8          1.4  ;

Scalar f  freight in dollars per case per thousand miles  /90/ ;

Parameter c(i,j)  transport cost in thousands of dollars per case ;

c(i,j) = f * d(i,j) / 1000 ;

Variables
x(i,j)  shipment quantities in cases
z       total transportation costs in thousands of dollars ;

Positive Variable x ;

Equations
cost        define objective function
supply(i)   observe supply limit at plant i
demand(j)   satisfy demand at market j ;

cost ..        z  =e=  sum((i,j), c(i,j)*x(i,j)) ;

supply(i) ..   sum(j, x(i,j))  =l=  a(i) ;

demand(j) ..   sum(i, x(i,j))  =g=  b(j) ;

Model transport /all/ ;

option limcol=0,limrow=0,solprint=off;

parameter dd;

scalar mode / 1/, cnt / 0 /;

set k(i,j), kval(i,j) ; k(i,j) = yes;

if(mode=1,
loop(k ,
kval(k) = yes;
display kval;
Solve transport using lp maximizing z ;
cnt := cnt + 1;
c(i,j) = c(i,j)*1.1; );
dd(i) = 10 );

set diff; diff(k) = yes - kval(k);

abort\$((cnt <> card(k)) or card(diff)) 'the loop did not run correctly',kval,diff;
``````
GAMS Development Corp.
GAMS Software GmbH

General Information and Sales
U.S. (+1) 202 342-0180
Europe: (+49) 221 949-9170