Decision Optimization

Decision Optimization

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  • 1.  Numer of Nodes in the Cplex MIP output

    Posted Thu January 16, 2014 09:46 AM

    Originally posted by: EvaMA


    Hi all, 

    I am using the CPLEX 12.5 Java API .

    When solving my MIP I'd like to find out how many nodes the solver produced when searching through the Branch-And-Cut-Tree. What I'm searching for is an output like this (from the CPLEX manual):

    Solution pool: 5 solutions saved. 
    MIP-Integer optimal solution:  Objective =   3.1860000000e+03
    Solution time =    0.01 sec.    Iterations = 131   Nodes = 44
    

    For my output I defined the following parameters: 

    cplex.setParam(IntParam.MIPInterval, 10);
    cplex.setParam(IntParam.MIPDisplay, 2); 

    Following information is displayed: 

    Tried aggregator 2 times.
    MIP Presolve eliminated 259162 rows and 332570 columns.
    Aggregator did 1320 substitutions.
    Reduced MIP has 115766 rows, 187359 columns, and 546843 nonzeros.
    Reduced MIP has 310 binaries, 0 generals, 0 SOSs, and 0 indicators.
    Presolve time = 2.43 sec. (813.21 ticks)
    Probing changed sense of 10 constraints.
    Probing time = 0.02 sec. (3.96 ticks)
    Tried aggregator 2 times.
    MIP Presolve eliminated 90 rows and 20 columns.
    MIP Presolve modified 280 coefficients.
    Aggregator did 30 substitutions.
    Reduced MIP has 115646 rows, 187309 columns, and 546193 nonzeros.
    Reduced MIP has 310 binaries, 0 generals, 0 SOSs, and 0 indicators.
    Presolve time = 0.75 sec. (234.35 ticks)
    Probing time = 0.03 sec. (3.91 ticks)
    Clique table members: 70.
    MIP emphasis: balance optimality and feasibility.
    MIP search method: dynamic search.
    Parallel mode: deterministic, using up to 4 threads.
    Root relaxation solution time = 5.63 sec. (1523.06 ticks)
     
            Nodes                                         Cuts/
       Node  Left     Objective  IInf  Best Integer    Best Bound    ItCnt     Gap
     
          0     0   156633.5972    10                 156633.5972    30774         
    *     0+    0                       156633.5972   156633.5972    30774    0.00%
          0     0        cutoff         156633.5972   156633.5972    30774    0.00%
    Elapsed time = 11.37 sec. (3007.60 ticks, tree = 0.00 MB, solutions = 1)
     
    Root node processing (before b&c):
      Real time             =    7.50 sec. (1825.32 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) =    7.50 sec. (1825.32 ticks) 

    Unfortunately the number of nodes is not included in the output. What can I do? Any ideas? 

    Thank you, 

    Eva


    #CPLEXOptimizers
    #DecisionOptimization


  • 2.  Re: Numer of Nodes in the Cplex MIP output

    Posted Thu January 16, 2014 12:31 PM


  • 3.  Re: Numer of Nodes in the Cplex MIP output

    Posted Sun January 19, 2014 07:45 AM

    Originally posted by: EvaMA


    Vielen Dank, thank you! That's exactly what I was looking for. 

    getNnodes() tells me that the number of nodes explored is zero, which explains that this information is not included to the conventional solver output.


    #CPLEXOptimizers
    #DecisionOptimization