CPLEX -Constraints 'C7' and 'C33' are inconsistent??

[Michael Sun]

Hi group,

 

we got a problem on sovling .mod and .dat with CPLEX.

It is said that Constraints 'C7' and 'C33' are inconsistent. infeasible problem.; no basis.

I want to know is there any problem with .mod and .dat; and how to know where is the error.

 

Appreciate for any replies.

 

Cheers

Mc

[Costas]

Try placing the following command before solve:

ampl: option auxfiles 'cr';

This should give you the names of the constraints that are
inconsistent. Most probably you will have to change the model.

[Robert Fourer]

Michael,

You can also see the content of the two constraints flagged by CPLEX by
means of the commands

expand _scon[7];
expand _scon[33];

CPLEX finds them to be "inconsistent" because, if all the other constraints
are satisfied, there is no way that these two constraints can both be
satisfied by the same values of the variables. It's up to you to figure out
why that is and to make appropriate corrections.

Bob Fourer
4...@iems.northwestern.edu