Description

Early cmex implementations used knock out list which was implemented
incorrcetly GT00512

Once a default value is stored at an index position, a second assignment
to the same index position (using a lag operator) will not store the
non-default value.

Small Model of Type : GAMS

Category : GAMS Test library

Main file : assign1.gms

$title lagged replacements could go wrong (ASSIGN1,SEQ=3)
$onText
Early cmex implementations used knock out list which was implemented
incorrcetly GT00512

Once a default value is stored at an index position, a second assignment
to the same index position (using a lag operator) will not store the
non-default value.
$offText

set i /i1*i3/;
parameter a(i) /i1=1, i2=2, i3=3/
          aa(i)
          b(i) /i1=0, i2=-1, i3=-2/
          c(i) /i1=10, i2=20, i3=30/
          cc(i) /i1=0, i2=20,i3=30 /;

a(i+b(i))=c(i); display a;
abort$(a('i1') <> c('i3')) 'lagged replacement is wrong';
aa(i) = a(i);
aa(i+b(i))=cc(i); display aa;
abort$(aa('i1') <> cc('i3')) 'lagged replacement is wrong';

set sa(i) /i1, i2, i3/;
set sc(i) /i2,i3/;

sa(i+b(i))=sc(i);
display sa;
abort$(not sa('i1')) 'lagged set is wrong';