Interactively including results

Many users desire to be able to execute another program during a GAMS job using some of the numbers resident in GAMS at that time then include the results in GAMS and continue onward.  Unfortunately, GAMS has not yet released general interface routines for the GDX file usage from other programs so one needs to use the existing spreadsheet or GAMS mechanisms.  One also can use an external program for constraint definition as discussed below.