Originally posted by: Nomykan

Today at 9:49 PM | Tags: none Add Tags

Hi, 

while solving an MIP problem the CPLEX engine shows "Row 'ct2#0#1#9#0' infeasible, all entries at implied bounds." i have gone through the posts and found that the problem is in constraint 2 but how to identify the other numbers to find out where the problem is infeasible. i am confused whether its the problem in constraint or problem in data? any help in this regard will be appreciated. Thanks

CPXPARAM_MIP_Tolerances_MIPGap                   0.02
CPXPARAM_MIP_Strategy_CallbackReducedLP          0
Row 'ct2#0#1#9#0' infeasible, all entries at implied bounds.
Presolve time = 0.11 sec. (74.55 ticks)

Root node processing (before b&c):
  Real time             =    0.16 sec. (102.97 ticks)
Parallel b&c, 4 threads:
  Real time             =    0.00 sec. (0.00 ticks)
  Sync time (average)   =    0.00 sec.
  Wait time (average)   =    0.00 sec.
                          ------------
Total (root+branch&cut) =    0.16 sec. (102.97 ticks)

Hi,

if you do not want to see # but the real indexes you should increase the big map threshold:

regards

Originally posted by: Nomykan

Hi Alex, 

Thanks for prompt reply but how to change this big map threshold limit? i have read the post but there is no method mentioned as how we can customize this big map value? 

getBigMapThreshold

public IloInt getBigMapThreshold() const

This member function returns the threshold set for arrays or maps to be considered big.

how and where we need to use this function for increasing big map value?

Thanks

Hi,

you may do that in a .ops file

regards

Originally posted by: Nomykan

Hi Alex, 

Thanks for the guidance. i have made the required changes in the ops file and also called in the flow control the ops settings but still i am not able to locate where the problem is. help me locate where i am wrong. Thanks

this is in the flow control i apply ops settings to the model.

 opl3.addDataSource(data5);
  opl3.applyOpsSettings(null, opl3.resolvePath("MainModel.ops"));
  opl3.generate();

And after the solution CPLEX engine now gives me like this

Total (root+branch&cut) =    0.38 sec. (301.87 ticks)
CPXPARAM_MIP_Tolerances_MIPGap                   0.050000000000000003
CPXPARAM_MIP_Strategy_CallbackReducedLP          0
Infeasibility row 'ct1#103#0#0':  0  = 38.
Presolve time = 0.03 sec. (15.92 ticks)

Hi,

have you added the .ops to the run configuration ?

Can you try with  1 000 000 as the limit ?

regards

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Originally posted by: Nomykan

Hi Alex,

Thanks for your help. This time it worked and i was able to locate the problem.