Decision Optimization

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Quite big model and .dat file with memory problem

  • 1.  Quite big model and .dat file with memory problem

    Posted 01/20/14 05:17 AM

    Originally posted by: pareto


    Dear all,

    I have been tackling with a very large model and data file.

    My .dat file 4.4GB, and my reduced MIP has 16954 rows, 1928330 columns, and 514035410 nonzeros.

    I ran 140GB of ram of 32 cores where only one in parallel is run. Hence, I use almost all memory.

    I ran my model with a tilim of 10h, and following log is foreseen:

    Setting initial solution
    1 of 1 MIP starts provided solutions.
    MIP start 'm1' defined initial solution with objective 269.0000.
    Presolve has eliminated 0 rows and 1 columns...
    Presolve has eliminated 31482 rows and 27247 columns...
    Presolve has eliminated 31482 rows and 27247 columns...
    Presolve has eliminated 31482 rows and 27247 columns...
    Tried aggregator 1 time.
    Presolve has eliminated 31482 rows and 27247 columns...
    MIP Presolve eliminated 31482 rows and 27247 columns.
    MIP Presolve modified 9795781 coefficients.
    Reduced MIP has 16954 rows, 1928330 columns, and 514035410 nonzeros.
    Reduced MIP has 1928330 binaries, 0 generals, 0 SOSs, and 0 indicators.
    Presolve time = 1491.20 sec. (896288.38 ticks)
    Probing time = 15.05 sec. (2781.92 ticks)
    Clique table members: 24158.
    MIP emphasis: hidden feasible solutions.
    MIP search method: dynamic search.
    Parallel mode: deterministic, using up to 5 threads.
    Root relaxation solution time = 3130.49 sec. (1177017.16 ticks)
     
            Nodes                                         Cuts/
       Node  Left     Objective  IInf  Best Integer    Best Bound    ItCnt     Gap
     
    *     0+    0                                      269.0000        0.0000    19583  100.00%
          0     0      191.3640   404      269.0000      191.3640    19583   28.86%

    I guess model crashes due to memory overflow. Is there any way that I can solve this model with less memory? I have formulated a lot of preprocessor, prober, thats is already reduced version.

    Thanks for help in advance

     

    #DecisionOptimization
    #OPLusingCPLEXOptimizer


  • 2.  Re: Quite big model and .dat file with memory problem

    Posted 01/20/14 02:15 PM

    Hi,

    can you try with cplex.threads=1;

    regards


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    #OPLusingCPLEXOptimizer


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