Hi
I have an LP model solving with Cplex solver. I have a 64 bit version of GAMS. my model is so huge.(after GAMS elimination, there are 250000 constrints and 350000 variables)
my problem is generating model takes so much time.
I set profile for the model and found out that the most time of the generating model is for “Solve Fini model” item, it takes 1333 secs.but solving model is taken about 180 seconds.
I want to know how can I reduce the generating time of the model.
can you give me any points for reducing this time?
Regards,
Kavosh
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Kavosh,
In default GAMS writes the model scratch files to disc, vacates memory and calls the solver (executable). Depending on disc speed (network drive ?) this could be slow, but what you describe is exceptionally slow. You can minimize disc activity by selecting a different solvelink option. Option solvelink=5; (before the solve statement) will instruct GAMS to communicate the model in memory and use the solver library. You will need sufficient core memory to make this option work. In case you do not need the variable and equation names inside the solver, you can instruct GAMS not to generate these names, by setting “modelname.dictfile=0;” before the solve statament (replace modelname with the actual name of the model you solve). If this all does not work, I suggest you send detailed information (listing file and potentially the entire model) to support@gams.com.
Hope this helps,
Michael Bussieck - GAMSWorld Coordinator
On Tuesday, June 16, 2015 at 10:33:26 AM UTC-4, Soheila wrote:
Hi
I have an LP model solving with Cplex solver. I have a 64 bit version of GAMS. my model is so huge.(after GAMS elimination, there are 250000 constrints and 350000 variables)
my problem is generating model takes so much time.
I set profile for the model and found out that the most time of the generating model is for “Solve Fini model” item, it takes 1333 secs.but solving model is taken about 180 seconds.
I want to know how can I reduce the generating time of the model.
can you give me any points for reducing this time?
Regards,
Kavosh
–
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