On reflection, and also after reading Xypron's comments, I agree with you. Xypron did enhance the wiki to make this point more visible to other users of GLPK.
-----Original Message----- From: Andrew Makhorin [mailto:[email protected]] Sent: Friday, January 14, 2011 7:26 AM To: Meketon, Marc Cc: [email protected] Subject: RE: [Help-glpk] The "dual" suffix and sensitivity to how a constraint is expressed in GMPL > 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. ---------------------------------------------------------------------------- This e-mail and any attachments may be confidential or legally privileged. If you received this message in error or are not the intended recipient, you should destroy the e-mail message and any attachments or copies, and you are prohibited from retaining, distributing, disclosing or using any information contained herein. Please inform us of the erroneous delivery by return e-mail. Thank you for your cooperation. ---------------------------------------------------------------------------- This e-mail and any attachments may be confidential or legally privileged. If you received this message in error or are not the intended recipient, you should destroy the e-mail message and any attachments or copies, and you are prohibited from retaining, distributing, disclosing or using any information contained herein. Please inform us of the erroneous delivery by return e-mail. Thank you for your cooperation. _______________________________________________ Help-glpk mailing list [email protected] http://lists.gnu.org/mailman/listinfo/help-glpk
