[SOLVED] CPLEX OPL : Overflow occurred, please use oplrun -profile

Issue

This Content is from Stack Overflow. Question asked by Ranajit

I am running a fairly large model in OPL, it has 576723 constraints, 1132515 variables, 3855 binary, 27150711 Non zero co-efficients.
At about 12 minutes the optimisation stops, it says 1 solution but displays no solution. In the profiler tab I get the Overflow occurred, please use oplrun -profile message.

The Engine log looks as below :

CPXPARAM_Emphasis_Memory                         1
CPXPARAM_MIP_Tolerances_AbsMIPGap                0.0001
CPXPARAM_MIP_Strategy_File                       2
CPXPARAM_Emphasis_MIP                            2
Found incumbent of value 0.000000 after 0.03 sec. (30.57 ticks)
Aggregator has done 1801 substitutions...
Aggregator has done 25001 substitutions...
Aggregator has done 47901 substitutions...
Aggregator has done 73901 substitutions...
Aggregator has done 106001 substitutions...
Aggregator has done 141801 substitutions...
Aggregator has done 183101 substitutions...
Aggregator has done 233701 substitutions...
Aggregator has done 306101 substitutions...
Tried aggregator 2 times.
MIP Presolve eliminated 159604 rows and 306975 columns.
MIP Presolve modified 3004144 coefficients.
Aggregator did 411847 substitutions.
Reduced MIP has 5269 rows, 413693 columns, and 11186321 nonzeros.
Reduced MIP has 2425 binaries, 0 generals, 0 SOSs, and 0 indicators.
Presolve time = 37.45 sec. (99718.43 ticks)
Tried aggregator 1 time.
Reduced MIP has 5269 rows, 413693 columns, and 11186321 nonzeros.
Reduced MIP has 2425 binaries, 0 generals, 0 SOSs, and 0 indicators.
Presolve time = 3.25 sec. (3033.58 ticks)
Probing time = 0.11 sec. (150.80 ticks)
Clique table members: 397.
MIP emphasis: optimality.
MIP search method: dynamic search.
Parallel mode: deterministic, using up to 16 threads.
Root relaxation solution time = 272.61 sec. (372380.11 ticks)

        Nodes                                         Cuts/
   Node  Left     Objective  IInf  Best Integer    Best Bound    ItCnt     Gap

*     0+    0                            0.0000   8.95478e+11              --- 
      0     0   4.84600e+11   436        0.0000   4.84600e+11    41973     --- 
      0     0        cutoff              0.0000                  81864     --- 
Elapsed time = 410.06 sec. (527413.16 ticks, tree = 0.01 MB, solutions = 1)

Root node processing (before b&c):
  Real time             =  410.17 sec. (527493.35 ticks)
Parallel b&c, 16 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) =  410.17 sec. (527493.35 ticks)

Kindly suggest how to overcome this problem.



Solution

Use better units. An objective value of 8.95478e+11 indicates you are using cents instead of billions of dollars. Also, make sure any big-M constants are not larger than needed.


This Question was asked in StackOverflow by Ranajit and Answered by Erwin Kalvelagen It is licensed under the terms of CC BY-SA 2.5. - CC BY-SA 3.0. - CC BY-SA 4.0.

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