Originally posted by: HansBB

Hello everyone,

I have the following Problem with big/large LP working with CPLEX 12.3 and Matlab:

The size of my LP depend on the Variable s.

If i set s=96*180 my LP looks like this:
obj: 207374x1 double
lb: 207374x1 double
ub: 207374x1 double
rhs: 449280x1 double
lhs: 449280x1 double
A: 449280x207374 double

I can solve this LP without problem, even if it takes a lot of time.

when i set s=96*360 my LP looks like this:
obj: 414734x1 double
lb: 414734x1 double
ub: 414734x1 double
rhs: 898560x1 double
lhs: 898560x1 double
A: 898560x414734 double

And when i try to solve this Problem i get: "CPLEX Error 1004: Null pointer for required data."

this is the output i get:
"ans =

[]

IBM ILOG License Manager: "IBM ILOG Optimization Suite for Academic Initiative" is accessing CPLEX >> >> "
so the solver not eaven starts with the Presolve, i guess.
Anyone have an idea of what could be going wrong?

Thank you in advance for your efforts.

Best regards,
Hans
#CPLEXOptimizers
#DecisionOptimization

Originally posted by: SystemAdmin

You may be facing out-of-memory issues here.
Can you try to export the model into a SAV file (using cplex.writeModel("model.sav")) and then try solve this model with the interactive optimizer? What is the output of that?
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#DecisionOptimization

Originally posted by: HansBB

Hello Daniel,

the output i get is the same.
Now i get the same problem but in point of saving the model:

"{Error using cplexlink123
CPLEX Error 1004: Null pointer for required data.
Error in
/home/.../ILOG/CPLEX_Studio_Academic123/cplex/matlab/@Cplex/Cplex.p>Cplex.writeModel
(line 1077)
Error in
/home/.../ILOG/CPLEX_Studio_Academic123/cplex/matlab/@Cplex/Cplex.p>Cplex.subsref
(line 3718)
Error in main (line 203)
cplex.writeModel('model.sav');
}"

I am working in the cluster of my university and i request a RAM of 200GB.
The feedback i get from the cluster looks like this:
"Resource usage summary:

CPU time : 353.63 sec.
Max Memory : 60353 MB
Max Swap : 83032 MB

Max Processes : 5
Max Threads : 10"
So i guess it is not a problem of running out of memory, because the resources i have seem to be enough.

Do you have any idea how can i fix this problem?

Thank you very much!

Regards,
Hans
#CPLEXOptimizers
#DecisionOptimization

Originally posted by: SystemAdmin

So you cannot even export the problem to file?
Right now I have no idea what might be the problem. Is it an option to upgrade to CPLEX 12.4 and check if the problem persists?
#CPLEXOptimizers
#DecisionOptimization

Originally posted by: HansBB

Hello Daniel,

with CPLEX 12.4 the same problem persist.
I think i have to model my problem otherwise.

anyway, thank you very much!

Regards,
Hans
#CPLEXOptimizers
#DecisionOptimization