Q: Is it possible to use a value instead the “+/- INF” string in the output file (which is generated by a put statement)?
There is no option or switch in GAMS that would do that. You could assign a large/small number of your choice to the parameters/variables with a
x(i,j)$(mapval(x(i,j))=6) = 1e300; x(i,j)$(mapval(x(i,j))=7) = -1e300;
or you could post process your output files with some batch editing tools like sed or awk (which is part of the GAMS distribution for Windows). Search Google for some sed/awk tutorials.