Xypron used "M" as a large constant (e.g., 9999). Not as a binary variable.
param M := 9999;
var B{J,K} >= 0;
s.t. a{j in J}: -M*sum{k in K}B[j,k] <= A[j] <= M*sum{k in K}B[j,k];
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of
Reginald Beardsley
Sent: Sunday, October 21, 2012 10:46 AM
To: glpk
Subject: [Help-glpk] "multiplication of linear forms not allowed"
I'm trying to apply the following constraint following a suggestion by xypron:
var M{J} ,binary;
var B{J,K} ,>= 0;
s.t. a{j}: -M[j]*sum{k in K}B[j,k] <= A[j] <= M[j]*sum{k in K}B[j,k];
The goal being to force A[j] = 0 if the sum over k of B[j,k] = 0;
glpsol 4.47 exits w/ the message in the subject line. I found Steglich's post
of last month, but am having trouble w/ translating the notation in the CMPL
1.7.0 manual to GMPL.
>From context, I'm guessing that overbar indicates the maximum and underbar the
>minimum, but I can find nothing to confirm that. The first equation in section
>8.3.1 appears to have a typo as there is no underbar in the range
>specification. Even if I assume the typo, and explicitly specify the
>additional variables and constraints, I still get the subject line message.
>Just at a different point.
Is it possible to do this in GMPL? If so, how?
At the moment, the only option I can see would be to make an initial solution
w/o the constraint and then recast the problem and solve again.
Thanks,
Reg
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