Dear Michael
I want to dedicate the maximum possible threads and memory of my computer to the GAMS solver (CPLEX). My model is a linear model which only includes continuous variables. I run my code in Grid computing environment. I set model option as follows:
modelname.threads=0;
It means the model can use all available cores. However I have some questions.
What is the relationship between this option (modelname.threads) and grid computing environment? ‘McCarl Expanded GAMS User’explains “Note that this does not alter the cores used in Grid computing.†about modelname.threads option.
How can I sure that the solver (CPLEX) uses the maximum available threads and RAM to speed up solution process? How can I monitor it? I monitored its process via task manager in windows but most of the time CPU and memory usage was below the %40 and %30 respectively. My laptop is core i7 with 8Gb RAM.
Thanks in advance;
Regards;
Hossein
On Thursday, October 16, 2014 10:46:32 AM UTC+3:30, Michael Bussieck wrote:
The ‘rerun = no’ is the correct one to supress the resolve with primal simplex to get more information. Unfortunately, we introduces a logical error in the GAMS/Cplex link when we extended the option to handle the fixed LP after solving a MIP problem. We have fixed this already and this will be available in the next release. In the meantime you can set ‘rerun nono’ and this will skip the solve with primal simplex. Thanks for unearthing this.
Michael
On Wednesday, October 15, 2014 3:29:28 PM UTC-4, hossein wrote:
Dear all
After the identification of my model as the infeasible model by GAMS, Cplex tries to solve it again, which is undesirable to me, as follows:
Removing perturbation.
LP status(3): infeasible
Cplex Time: 0.78sec (det. 372.14 ticks)
Dual infeasible or unbounded. Switching to primal to aid diagnosis.
Tried aggregator 1 time.
LP Presolve eliminated 304797 rows and 302399 columns.
Aggregator did 964 substitutions.
Reduced LP has 1205 rows, 1717 columns, and 6116 nonzeros.
Presolve time = 0.25 sec. (92.91 ticks)
Using devex.
Iteration log . . .
Iteration: 1 Scaled infeas = 38.509142
Iteration: 158 Scaled infeas = 14.912938
LP status(3): infeasible
Cplex Time: 0.81sec (det. 408.69 ticks)
Model has been proven infeasible.
I tied to disable the ‘Switching to primal to aid diagnosis’ step by commands as follows:
putclose opts /‘rerun = NO’ /‘feasopt = NO’;
But noting was changed. Can anyone help me to remove this step?
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