Re: [Help-glpk] Remove constraint

[Nilo Cesar Teixeira]

Try 'fr[r]..1 by -1'

The by makes it count in reverse order.

(page 16 of manual, Arithmetic set).

2011/11/2 Kasper Tordrup <address@hidden>

Hi Guys
I came across a weird bug or maybe it was just me that was doing something stupid.
I had this constraint:
s.t. overlap1{r in R, j in fr[r]..1}: sum{s in S, i in max(1,j-hs[s]+1)..j} x[s,r,i] <= 1;
but GLPK kept violating it. I tried making the sum in the end of my .mod file (after solve;) and I could see that there was a clear violation.
I could see in my shell that it was generating the constraint, but when I checked the output file there was no values for overlap1 like it has just ignored the constraint?
I then played a little with the constraint and changed it to:
s.t. overlap1{r in R, j in 1..fr[r]}: sum{s in S, i in max(1,j-hs[s]+1)..j} x[s,r,i] <= 1;
only changed "fr[r]..1" to "1..fr[r]" and now it works perfectly. Is there some logical explanation that I'm missing?

Best regards,
Kasper

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Nilo Cesar Teixeira
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