$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';