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 <[email protected]>

> 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
>
> _______________________________________________
> Help-glpk mailing list
> [email protected]
> https://lists.gnu.org/mailman/listinfo/help-glpk
>
>


-- 
*Nilo Cesar Teixeira*
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