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Re: [Help-glpk] "multiplication of linear forms not allowed"
From: |
Mike Steglich |
Subject: |
Re: [Help-glpk] "multiplication of linear forms not allowed" |
Date: |
Mon, 22 Oct 2012 07:25:56 +0200 |
Hi Reginald,
Can you post the original mathematical description of your problem for a better
understanding?
Thanks,
Mike
Am 21.10.2012 um 16:45 schrieb Reginald Beardsley:
>
> 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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