[Cbc] mps error

John J Forrest jjforre at us.ibm.com
Mon Sep 24 10:21:56 EDT 2007


Thank you for sending me the mps file.

I am surprised that glpk had no problems solving the problem.

If you look at the mps file you sent you will see that row R0000092 is an 
equality row with rhs of 0.0 and one element, a +1 in column C0002992. 
C0002992 is fixed to 1in the bounds section so obviously the problem is 
infeasible as reported.

John Forrest



Spring <springsender at yahoo.it> 
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09/21/2007 10:34 AM

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Subject
[Cbc] mps error






Hi, 
I'm trying to solve a Binary optimization problem by using both coin-or 
cbc an glpk solver. In particular I'm using glpk to create the mps file 
for the problem and cbc to solve it.
My optimization problem is the following: I'have 30 cars and 374 park rows 
and I have to find the best parking.
I have choose to solve firstly the problem with 20 cars and all the park 
rows, I've obtained the solution and now I want to solve the problem with 
30 cars and all the rows by fixing to 1 the variables obtained like 
results with 20 cars but when I give the generated mps file to cbc I've 
the following error:
Model was imported from 
D:/workspace/OptimizationProject/info/optimizationFiles/F2cv_ProblemDescription.mps 
in 2.303 seconds
1 infeasibilities
Problem is infeasible - tightenPrimalBounds!

What's the problem?
I've solved in the same way the problem with Glpk and I've no errors.

Thanks
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