Hi
I am solving a problem where root relaxation taking longer time. How I can improve the performance? please suggest, below are the logs
Starting optimization...
Version identifier: 22.1.2.0 | 2024-12-02 | 8bd2200c8
CPXPARAM_Read_DataCheck 1
CPXPARAM_TimeLimit 3600
CPXPARAM_MIP_Tolerances_MIPGap 0.02
Legacy callback i
Presolve has eliminated 181061 rows and 99822 columns...
Presolve has improved bounds 59698 times...
Tried aggregator 2 times.
Aggregator has done 54685 substitutions...
MIP Presolve eliminated 181608 rows and 114308 columns.
MIP Presolve modified 86315 coefficients.
Aggregator did 54685 substitutions.
Reduced MIP has 34607 rows, 6483380 columns, and 12987091 nonzeros.
Reduced MIP has 6473835 binaries, 9545 generals, 0 SOSs, and 0 indicators.
Presolve time = 43.18 sec. (200055.45 ticks)
Tried aggregator 1 time.
Detecting symmetries...
Elapsed time for symmetry detection = 2.13 sec. (10001.81 ticks)
Elapsed time for symmetry detection = 3.73 sec. (20031.20 ticks)
Elapsed time for symmetry detection = 5.51 sec. (30063.25 ticks)
Elapsed time for symmetry detection = 7.55 sec. (40090.37 ticks)
Elapsed time for symmetry detection = 9.60 sec. (50148.78 ticks)
Elapsed time for symmetry detection = 11.95 sec. (60210.88 ticks)
Elapsed time for symmetry detection = 14.20 sec. (70271.72 ticks)
Elapsed time for symmetry detection = 16.59 sec. (80330.47 ticks)
Elapsed time for symmetry detection = 18.85 sec. (90387.95 ticks)
Found 1.075511e+34192 symmetric permutations.
MIP Presolve eliminated 0 rows and 12 columns.
MIP Presolve modified 24 coefficients.
Reduced MIP has 34607 rows, 6483368 columns, and 12987079 nonzeros.
Reduced MIP has 6473823 binaries, 9545 generals, 0 SOSs, and 0 indicators.
Presolve time = 26.28 sec. (99983.16 ticks)
Probing time = 12.69 sec. (1733.54 ticks)
Clique table members: 14628.
MIP emphasis: balance optimality and feasibility.
MIP search method: dynamic search.
Parallel mode: deterministic, using up to 8 threads.
Root relaxation solution time = 597.53 sec. (180057.57 ticks)
Nodes Cuts/
Node Left Objective IInf Best Integer Best Bound ItCnt Gap
0 0 2197.6190 2 2197.6190 8613
* 0+ 0 2300.0000 2197.6190 4.45%
0 0 cutoff 2300.0000 8635 0.00%
Elapsed time = 761.12 sec. (613616.94 ticks, tree = 0.01 MB, solutions = 1)
Root node processing (before b&c):
Real time = 761.52 sec. (613887.58 ticks)
Parallel b&c, 8 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) = 761.52 sec. (613887.58 ticks)
Benchmark results written to: Cplex_Benchmark_Data_10percent.csv
Solve status : integer optimal solution
Solve time : 761.52s
Objective : 2300.0000