[Cbc] How to turn off cuts and preprocessing?

[Ashutosh Mahajan]

I want to turn off all cuts, all heuristics AND all preprocessing.

If I try
./bin/cbc egout.mps -cuts off -heur off -preprocess off solve

then the cuts are still generated. Surprisingly, if I turn on the preprocessing,

/bin/cbc egout.mps -cuts off -heur off -preprocess on solve
then cuts are disabled.

I am using cbc stable 2.8. Here is the output. Am I doing something
wrong? Thanks in advance. Cheers.

Ashutosh.


Welcome to the CBC MILP Solver
Version: 2.8
Build Date: Jan 30 2013
Revision Number: 1862

command line - ./bin/cbc /home/amahajan/instances/deluge/egout.mps
-cuts off -heur off -preprocess off solve (default strategy 1)
At line 15 NAME          EGOUT
At line 16 ROWS
At line 116 COLUMNS
At line 315 RHS
At line 316 BOUNDS
At line 403 ENDATA
Problem EGOUT has 98 rows, 141 columns and 282 elements
Coin0008I EGOUT read with 0 errors
Option for cutsOnOff changed from on to off
Option for heuristicsOnOff changed from on to off
Option for preprocess changed from sos to off
Continuous objective value is 149.589 - 0.00 seconds
Cbc0010I After 0 nodes, 1 on tree, 1e+50 best solution, best possible
367.08488 (0.00 seconds)
Cbc0016I Integer solution of 624.70162 found by strong branching after
519 iterations and 12 nodes (0.01 seconds)
Cbc0038I Full problem 98 rows 141 columns, reduced to 37 rows 49 columns
Cbc0044I Reduced cost fixing - 37 rows, 49 columns - restarting search
Cbc0012I Integer solution of 624.70162 found by Previous solution
after 0 iterations and 0 nodes (0.00 seconds)
Cbc0031I 12 added rows had average density of 5.1666667
Cbc0013I At root node, 12 cuts changed objective from 511.58538 to
568.1007 in 4 passes
Cbc0014I Cut generator 0 (Probing) - 21 row cuts average 2.0 elements,
0 column cuts (12 active)  in 0.000 seconds - new frequency is -100
Cbc0014I Cut generator 1 (Gomory) - 13 row cuts average 10.7 elements,
0 column cuts (0 active)  in 0.000 seconds - new frequency is -100
Cbc0014I Cut generator 2 (Knapsack) - 1 row cuts average 2.0 elements,
0 column cuts (0 active)  in 0.000 seconds - new frequency is -100
Cbc0014I Cut generator 3 (Clique) - 0 row cuts average 0.0 elements, 0
column cuts (0 active)  in 0.000 seconds - new frequency is -100
Cbc0014I Cut generator 4 (FlowCover) - 6 row cuts average 3.8
elements, 0 column cuts (0 active)  in 0.000 seconds - new frequency
is -100
Cbc0014I Cut generator 5 (MixedIntegerRounding2) - 11 row cuts average
5.7 elements, 0 column cuts (0 active)  in 0.000 seconds - new
frequency is -100
Cbc0004I Integer solution of 568.1007 found after 28 iterations and 0
nodes (0.00 seconds)
Cbc0001I Search completed - best objective 568.1006999999998, took 28
iterations and 0 nodes (0.00 seconds)
Cbc0035I Maximum depth 0, 0 variables fixed on reduced cost
Cbc0038I Probing was tried 4 times and created 21 cuts of which 12
were active after adding rounds of cuts (0.000 seconds)
Cbc0038I Gomory was tried 4 times and created 13 cuts of which 0 were
active after adding rounds of cuts (0.000 seconds)
Cbc0038I Knapsack was tried 4 times and created 1 cuts of which 0 were
active after adding rounds of cuts (0.000 seconds)
Cbc0038I Clique was tried 4 times and created 0 cuts of which 0 were
active after adding rounds of cuts (0.000 seconds)
Cbc0038I FlowCover was tried 4 times and created 6 cuts of which 0
were active after adding rounds of cuts (0.000 seconds)
Cbc0038I MixedIntegerRounding2 was tried 4 times and created 11 cuts
of which 0 were active after adding rounds of cuts (0.000 seconds)
Cbc0012I Integer solution of 568.1007 found by Reduced search after
1491 iterations and 50 nodes (0.04 seconds)
Cbc0001I Search completed - best objective 568.1007000000001, took
1491 iterations and 50 nodes (0.04 seconds)
Cbc0032I Strong branching done 404 times (649 iterations), fathomed 18
nodes and fixed 29 variables
Cbc0035I Maximum depth 11, 8 variables fixed on reduced cost
Cuts at root node changed objective from 347.637 to 367.085

Result - Optimal solution found

Objective value:                568.10070000
Enumerated nodes:               50
Total iterations:               1491
Time (CPU seconds):             0.04
Time (Wallclock seconds):       0.05

Total time (CPU seconds):       0.04   (Wallclock seconds):       0.05



Welcome to the CBC MILP Solver
Version: 2.8
Build Date: Jan 30 2013
Revision Number: 1862

command line - ./bin/cbc /home/amahajan/instances/deluge/egout.mps
-cuts off -heur off -preprocess on solve (default strategy 1)
At line 15 NAME          EGOUT
At line 16 ROWS
At line 116 COLUMNS
At line 315 RHS
At line 316 BOUNDS
At line 403 ENDATA
Problem EGOUT has 98 rows, 141 columns and 282 elements
Coin0008I EGOUT read with 0 errors
Option for cutsOnOff changed from on to off
Option for heuristicsOnOff changed from on to off
Option for preprocess changed from sos to on
Continuous objective value is 149.589 - 0.00 seconds
Cgl0003I 0 fixed, 0 tightened bounds, 14 strengthened rows, 0 substitutions
Cgl0004I processed model has 36 rows, 48 columns (28 integer) and 97 elements
Cbc0010I After 0 nodes, 1 on tree, 1e+50 best solution, best possible
511.61742 (0.00 seconds)
Cbc0016I Integer solution of 583.453 found by strong branching after
19 iterations and 7 nodes (0.00 seconds)
Cbc0016I Integer solution of 575.57088 found by strong branching after
19 iterations and 7 nodes (0.00 seconds)
Cbc0016I Integer solution of 568.1007 found by strong branching after
30 iterations and 14 nodes (0.00 seconds)
Cbc0001I Search completed - best objective 568.1007, took 122
iterations and 46 nodes (0.02 seconds)
Cbc0032I Strong branching done 276 times (393 iterations), fathomed 22
nodes and fixed 15 variables
Cbc0035I Maximum depth 6, 53 variables fixed on reduced cost
Cuts at root node changed objective from 511.617 to 511.617

Result - Optimal solution found

Objective value:                568.10070000
Enumerated nodes:               46
Total iterations:               122
Time (CPU seconds):             0.02
Time (Wallclock seconds):       0.02

Total time (CPU seconds):       0.02   (Wallclock seconds):       0.02