Re: [Help-glpk] Problem Has no Primal Feasible Solution

[Daniele Micarelli]

[Help-glpk] Problem Has no Primal Feasible Solution

I think that this problem has solution because i have solved it mentally with only 10 acitivities, but also with 10 activities GLPSOL says that the problem has no primal feasible solution.

By testing I realized that the causes of the error is precisely this constraint

with this constraint I would say that each activities begins immediately after the end of the previous activity

how can i change this constraint?

thank you very much

2012/7/7 glpk xypron <address@hidden>

Hello Daniele,

take a look at this constraint:

/* temporal precedence constraint */
subject to PrecTemp{i in A,j in A}: sum{t in T} tt[t]*x[j,t] >= sum{t in T} tt[t]*x[i,t] + d[i];

For i = j it requires non-positive durations 0 >= d[i].

Best regards

Xypron

-------- Original-Nachricht --------
> Datum: Fri, 6 Jul 2012 12:25:58 +0200
> Von: Daniele Micarelli <address@hidden>
> An: address@hidden
> Betreff: [Help-glpk] Problem Has no Primal Feasible Solution

> Hi,
> i'm attaching the two file  .mod and .dat to let you know
>
> When i run these files with glpsol,  i get these two messages at the end:
>

> *Model has been successfully generated

> and
> PROBLEM HAS NO PRIMAL FEASIBLE SOLUTION
>

> *in my opinion should exist one solution
>
> it's possible?