> To me, the only issues are: > (a) Should GMPL be more clever and check if all the variables are only on one > side of the constraint, and if so always place the variables on the > left-side, > and the constant on the right side, and not multiply by -1? That would > create > more intuitive dual variables.
Then it would be unclear what to do, say, with the following constraint: x1 + x2 + x3 = x4 + x5 + x6 Besides, in the primal case the rule you suggest is similar to a rule, when, for example, a variable declared as x <= 0 is replaced by x >= 0 for the same reason. It seems to me that a "more clever" rule for transforming constraints to the standard format would be more confusing. _______________________________________________ Help-glpk mailing list [email protected] http://lists.gnu.org/mailman/listinfo/help-glpk
