Re: [Help-glpk] "multiplication of linear forms not allowed"

[Mike Steglich]

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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