- The Windows executables are not built with parallel threading support.
- The CSV writer is too simplistic. Names (with commas in them) are not properly quoted.
Threads option ignored
| C:\projects\test>cbc model1a.lp ratio 0.05 threads 8 solve printing csv solution model1a.csv Welcome to the CBC MILP Solver Version: 2.8.8 Build Date: Dec 23 2013 Revision Number: 1998 command line - cbc model1a.lp ratio 0.05 threads 8 solve printing csv solution model1a.csv (default strategy 1) ratioGap was changed from 0 to 0.05 No match for threads - ? for list of commands No match for 8 - ? for list of commands Continuous objective value is 57.0769 - 0.02 seconds Cgl0002I 30 variables fixed Cgl0003I 0 fixed, 0 tightened bounds, 527 strengthened rows, 0 substitutions Cgl0003I 0 fixed, 0 tightened bounds, 475 strengthened rows, 0 substitutions Cgl0003I 0 fixed, 0 tightened bounds, 429 strengthened rows, 0 substitutions Cgl0003I 0 fixed, 0 tightened bounds, 291 strengthened rows, 0 substitutions Cgl0003I 0 fixed, 0 tightened bounds, 69 strengthened rows, 0 substitutions Cgl0004I processed model has 743 rows, 499 columns (346 integer) and 2429 elements Cbc0038I Pass 1: suminf. 0.00000 (0) obj. 12146 iterations 431 Cbc0038I Solution found of 12146 Cbc0038I Before mini branch and bound, 316 integers at bound fixed and 140 continuous Cbc0038I Full problem 743 rows 499 columns, reduced to 247 rows 145 columns Cbc0038I Mini branch and bound improved solution from 12146 to 166 (0.50 seconds) 0 Obj 166 Dual inf 0.22137435 (11) End of values pass after 26 iterations 26 Obj 166 Dual inf 549.2981 (110) Perturbing problem by 0.001 % of 0.92934395 - largest nonzero change 1.9181672e-005 (% 0.0011298852) - largest zero chan ge 1.9246056e-005 120 Obj 166 Optimal - objective value 166 Cbc0038I Round again with cutoff of 164.5 Cbc0038I Pass 2: suminf. 7.33333 (22) obj. 164.5 iterations 163 Cbc0038I Pass 3: suminf. 6.22857 (20) obj. 164.5 iterations 71 Cbc0038I Pass 4: suminf. 5.33336 (18) obj. 164.5 iterations 34 Cbc0038I Pass 5: suminf. 4.10000 (14) obj. 164.5 iterations 28 Cbc0038I Pass 6: suminf. 0.00750 (3) obj. 164.5 iterations 166 Cbc0038I Solution found of 162 Cbc0038I Before mini branch and bound, 311 integers at bound fixed and 141 continuous Cbc0038I Full problem 743 rows 499 columns, reduced to 296 rows 158 columns Cbc0038I Mini branch and bound did not improve solution (0.74 seconds) Cbc0038I Round again with cutoff of 159.8 Cbc0038I Pass 7: suminf. 8.02667 (26) obj. 159.8 iterations 29 Cbc0038I Pass 8: suminf. 7.10546 (36) obj. 159.8 iterations 122 Cbc0038I Pass 9: suminf. 7.12365 (46) obj. 159.8 iterations 40 Cbc0038I Pass 10: suminf. 18.70686 (90) obj. 159.8 iterations 281 Cbc0038I Pass 11: suminf. 9.66191 (71) obj. 159.8 iterations 220 Cbc0038I Pass 12: suminf. 9.07849 (73) obj. 159.8 iterations 59 Cbc0038I Pass 13: suminf. 9.67900 (63) obj. 159.8 iterations 157 Cbc0038I Pass 14: suminf. 8.05376 (64) obj. 159.8 iterations 92 Cbc0038I Pass 15: suminf. 9.90251 (61) obj. 159.8 iterations 100 Cbc0038I Pass 16: suminf. 8.87667 (61) obj. 159.8 iterations 59 Cbc0038I Pass 17: suminf. 11.47273 (46) obj. 159.8 iterations 120 Cbc0038I Pass 18: suminf. 10.18668 (44) obj. 159.8 iterations 33 Cbc0038I Pass 19: suminf. 7.58501 (60) obj. 159.8 iterations 60 Cbc0038I Pass 20: suminf. 6.99899 (78) obj. 159.8 iterations 36 Cbc0038I Pass 21: suminf. 7.66668 (32) obj. 159.8 iterations 128 Cbc0038I Pass 22: suminf. 7.13455 (64) obj. 159.8 iterations 106 Cbc0038I Pass 23: suminf. 7.20358 (59) obj. 159.8 iterations 80 Cbc0038I Pass 24: suminf. 7.13455 (64) obj. 159.8 iterations 67 Cbc0038I Pass 25: suminf. 8.20892 (48) obj. 159.8 iterations 257 Cbc0038I Pass 26: suminf. 7.32000 (30) obj. 159.8 iterations 124 Cbc0038I Pass 27: suminf. 9.03479 (27) obj. 159.8 iterations 92 Cbc0038I Pass 28: suminf. 7.34334 (33) obj. 159.8 iterations 59 Cbc0038I Pass 29: suminf. 7.32000 (30) obj. 159.8 iterations 53 Cbc0038I Pass 30: suminf. 7.32000 (30) obj. 159.8 iterations 31 Cbc0038I Pass 31: suminf. 16.85062 (65) obj. 159.8 iterations 288 Cbc0038I Pass 32: suminf. 5.71250 (21) obj. 159.8 iterations 277 Cbc0038I Pass 33: suminf. 5.00000 (15) obj. 159.8 iterations 69 Cbc0038I Pass 34: suminf. 5.00000 (15) obj. 159.8 iterations 72 Cbc0038I Pass 35: suminf. 5.00000 (15) obj. 159.8 iterations 136 Cbc0038I Pass 36: suminf. 9.86669 (43) obj. 159.8 iterations 256 Cbc0038I No solution found this major pass Cbc0038I Before mini branch and bound, 178 integers at bound fixed and 89 continuous Cbc0038I Full problem 743 rows 499 columns, reduced to 542 rows 307 columns - 15 fixed gives 331, 197 - ok now Cbc0038I Full problem 743 rows 499 columns, reduced to 328 rows 197 columns Cbc0038I Mini branch and bound did not improve solution (1.22 seconds) Cbc0038I After 1.23 seconds - Feasibility pump exiting with objective of 162 - took 0.92 seconds Cbc0012I Integer solution of 162 found by feasibility pump after 0 iterations and 0 nodes (1.24 seconds) Cbc0038I Full problem 743 rows 499 columns, reduced to 317 rows 154 columns Cbc0038I Full problem 743 rows 499 columns, reduced to 0 rows 0 columns Cbc0031I 19 added rows had average density of 171.78947 Cbc0013I At root node, 19 cuts changed objective from 151 to 154.55353 in 100 passes Cbc0014I Cut generator 0 (Probing) - 207 row cuts average 2.5 elements, 7 column cuts (7 active) in 0.203 seconds - new frequency is 1 Cbc0014I Cut generator 1 (Gomory) - 1562 row cuts average 349.6 elements, 0 column cuts (0 active) in 0.842 seconds - n ew frequency is 1 Cbc0014I Cut generator 2 (Knapsack) - 0 row cuts average 0.0 elements, 0 column cuts (0 active) in 0.094 seconds - new frequency is -100 Cbc0014I Cut generator 3 (Clique) - 0 row cuts average 0.0 elements, 0 column cuts (0 active) in 0.037 seconds - new fr equency is -100 Cbc0014I Cut generator 4 (MixedIntegerRounding2) - 0 row cuts average 0.0 elements, 0 column cuts (0 active) in 1.313 s econds - new frequency is -100 Cbc0014I Cut generator 6 (TwoMirCuts) - 191 row cuts average 191.0 elements, 0 column cuts (0 active) in 0.253 seconds - new frequency is 1 Cbc0011I Exiting as integer gap of 7.4464682 less than 1e-010 or 5% Cbc0001I Search completed - best objective 162, took 17263 iterations and 0 nodes (6.98 seconds) Cbc0035I Maximum depth 0, 42 variables fixed on reduced cost Cuts at root node changed objective from 151 to 154.554 Probing was tried 100 times and created 214 cuts of which 0 were active after adding rounds of cuts (0.203 seconds) Gomory was tried 100 times and created 1562 cuts of which 0 were active after adding rounds of cuts (0.842 seconds) Knapsack was tried 100 times and created 0 cuts of which 0 were active after adding rounds of cuts (0.094 seconds) Clique was tried 100 times and created 0 cuts of which 0 were active after adding rounds of cuts (0.037 seconds) MixedIntegerRounding2 was tried 100 times and created 0 cuts of which 0 were active after adding rounds of cuts (1.313 s econds) FlowCover was tried 1 times and created 0 cuts of which 0 were active after adding rounds of cuts (0.000 seconds) TwoMirCuts was tried 100 times and created 191 cuts of which 0 were active after adding rounds of cuts (0.253 seconds) Result - Optimal solution found (within gap tolerance) Objective value: 162.00000000 Lower bound: 154.554 Gap: 0.05 Enumerated nodes: 0 Total iterations: 17263 Time (CPU seconds): 7.05 Time (Wallclock seconds): 7.05 Option for printingOptions changed from normal to csv Total time (CPU seconds): 7.08 (Wallclock seconds): 7.08 C:\projects\test> |
A better error message could indicate this executable was not compiled with parallel threading support.
I think parallel CBC does not work very well on Windows. I have tried also a GAMS version of the model using GAMS/CBC with threads=8. This leads to a crash:
Looks like this is just not working very well. May be it is good threads are disabled in the Windows executable from the binary dsitribution.
Incorrect CSV output
The column name has some embedded commas, so the name should be quoted by the CSV writer. Here is a fragment of the output.| Assign(Student1,MON,m3),0 Assign(Student1,SCH,m1),1 Assign(Student1,MON,m4),0 Assign(Student1,MON,m7),0 Assign(Student1,MON,m8),0 Assign(Student1,GES,m11),0 Assign(Student1,GES,m12),0 Assign(Student1,GES,m13),0 |
Update: running on Mac (GAMS/CBC)
This also looks very scary (memory overruns?):
| Maximum depth 0, 6 variables fixed on reduced cost 7 added rows had average density of 51.857143 At root node, 17 cuts changed objective from 158.29268 to 161.10418 in 8 passes Cut generator 0 (Gomory) - 37 row cuts average 58.3 elements, 0 column cuts (12 active) CutS egaerncehr actoomrp l0e t(eGdo m-o rbye)s t- o3b7j ercotwi vceu t1se +a5v0e,r atgoeo k5 82.039 eilteemreanttiso,n s0 acnodl u0m nn ocduetss ((1182. 5a5c tsievceo nds) Maximum depth 0, 6 variables fixed on reduced cost |
The CBC log is pretty dense and messy (matter of taste of course), so not always easy to see strange messages, but this gibberish is of course a sign of a problem.
Update2: Mac again
After recompiling from sources I could run the problem with multiple threads (when reading from MPS files). May be a build problem in the GAMS version of CBC. But now I see my LP files are no longer accepted:| Coin3007W ### CoinLpIO::is_invalid_name(): Name is empty Coin3007W ### CoinLpIO::are_invalid_names(): Invalid name: vnames[1396]: (null) Coin3007W ### CoinLpIO::setLpDataRowAndColNames(): Invalid row names |
Not a very clear message. I would like to see what I should do to fix my file. The solution is bogus so the lp file is read in incorrectly. (To be complete: this was tar file version 2.8.12). I am not a happy camper…
No comments:
Post a Comment