Typically you define two non-negative variables, say rPlus and rNegative whose difference is (1-y) and [with the correct objective function] whose sum is the absolute value of (1-y).
The code is something like: var rPlus >=0; var rNegative >=0; maximize obj - (rPlus + rNegative); subject to AbsoluteValueTypeConstraint 1-y = rPlus - rNegative; Note that rPlus+rNegative is the absolute value of (1-y) when that sum is minimized. ________________________________ From: [email protected] [mailto:[email protected]] On Behalf Of name name Sent: Saturday, November 20, 2010 7:29 AM To: [email protected] Subject: [Help-glpk] abs Hello, I want to calculate var y,>=0; maximize obj: abs(1-y); fa: ... fb: ... solve; ... data; ... I get the argument for abs has invalide type, could you tell me how I could do this? Is it possible to solve the maximization probleme several times? something like this var y,>=0; {k in 1 .. 20} : /* To get the solution for k=1, solution for k=2 ...*/ maximize obj: abs(1-y); fa: ... fb: ... solve; ... data; ... And the last question How can I compile an model model.mod where the data is in a file model.dat Thank you a lot Onor ---------------------------------------------------------------------------- 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.
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