What's mean "no basis" in this problem?

[Cristian Vera]

Dear all.

I'm relatively new on AMPL, so I have a problem to resolve a problem of three stage production, distribution and planing with capacity expansion.

Basically I need solve a model that appears in this paper Strategic level three-stage production distribution planning with capacity expansion (https://www.sciencedirect.com/science/article/abs/pii/S0360835206000490). 

This paper consist in determine the optimal solution of  produce one product with a number of suppliers and distribution centers, with the option to expand the capacity with a respective cost.

When I solve this model, It appears to me:

CPLEX 12.4.0.0: integer infeasible.

0 MIP simplex iterations

0 branch-and-bound nodes

No basis.

costo = 0

The parameters: demand, transport cost from supplier to producer and transport cost from producer to distributor are a uniform distribution. 

And I don't understand, Why appears this, if I write the model exactly as it appears in the paper?

I attach this files.

Thank you so much for your help.

P.D. Excuse my English, I don't know write well and it's difficult to me.

[AMPL Google Group]

You can use iis feature described in https://ampl.com/BOOK/CHAPTERS/17-solvers.pdf to identify the infeasibility in your model. When I ran your model, it seems that you have problem in R7 constraint. When I modified your equality constraint to inequality constraint (<= ) constraint, I obtained the optimal solution. Your problem might be infeasible with the equality constraint.

Thanks,
Paras

--
Paras Tiwari
am...@googlegroups.com

{#HS:567263628-5948#}

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