[Cbc] CBC Stable 2.3 stuck on tiny MIP

[Matthew Galati]

I get  the following and have to kill the process to get it to stop. Running through gdb, breaking, continuing, etc - it is not clear where it gets stuck - but seems to be in some kind of infinite loop. If you still cannot repeat, I can try to debug it later when I have time.

[magala at orclus71 bin]$ uname -a
Linux orclus71 2.6.18-8.el5 #1 SMP Fri Jan 26 14:15:14 EST 2007 x86_64 x86_64 x86_64 GNU/Linux
[magala at orclus71 bin]$ gcc -v
Using built-in specs.
Target: x86_64-redhat-linux
Configured with: ../configure --prefix=/usr --mandir=/usr/share/man --infodir=/usr/share/info --enable-shared --enable-threads=posix --enable-checking=release --with-system-zlib --enable-__cxa_atexit --disable-libunwind-exceptions --enable-libgcj-multifile --enable-languages=c,c++,objc,obj-c++,java,fortran,ada --enable-java-awt=gtk --disable-dssi --enable-plugin --with-java-home=/usr/lib/jvm/java-1.4.2-gcj-1.4.2.0/jre --with-cpu=generic --host=x86_64-redhat-linux
Thread model: posix
gcc version 4.1.1 20070105 (Red Hat 4.1.1-52)

Coin Cbc and Clp Solver version 2.3stable, build Oct  5 2009
command line - ./cbc /users/magala/PRICE_AND_CUT_subProb_relax.n21.c0.p5.b0.lp -log 10 -solve -quit (default strategy 1)
logLevel was changed from 1 to 10
Continuous objective value is -9372.08 - 0.00 seconds
Cgl0010I element in row 1 for column 9 changed from -230 to -5
Cgl0010I element in row 1 for column 15 changed from -200 to -5
Cgl0010I element in row 1 for column 16 changed from -400 to -5
Cgl0010I element in row 4 for column 1 changed from -300 to -5
Cgl0010I element in row 4 for column 17 changed from -200 to -5
Cgl0010I element in row 4 for column 18 changed from -400 to -5
Cgl0009I 6 elements changed
Cgl0003I 0 fixed, 0 tightened bounds, 2 strengthened rows, 0 substitutions
Cgl0003I 0 fixed, 0 tightened bounds, 2 strengthened rows, 0 substitutions
Cgl0003I 0 fixed, 0 tightened bounds, 2 strengthened rows, 0 substitutions
Cgl0003I 0 fixed, 0 tightened bounds, 2 strengthened rows, 0 substitutions
Cgl0004I processed model has 6 rows, 20 columns (20 integer) and 30 elements
Setting increment of 0 accumulate of 1 7 retries and setting when to 53
Cbc0038I Solution found of -9120.53
Cbc0038I Branch and bound needed to clear up 1 general integers
Cgl0009I 1 elements changed
Cgl0009I 1 elements changed
Cgl0004I processed model has 2 rows, 5 columns (5 integer) and 7 elements
Cbc0038I Full problem 6 rows 20 columns, reduced to 2 rows 5 columns
Cbc0028I Starting sub-tree for CbcHeuristicFpump - maximum nodes 200
Cbc0013I At root node, 0 cuts changed objective from -9120.53 to -9053.03 in 2 passes
Cbc0014I Cut generator 0 (Probing) - 0 row cuts, 2 column cuts (2 active)
Cbc0010I After 0 nodes, 1 on tree, 1e+50 best solution, best possible -9053.03 (0.00 seconds)
Cbc0015I Node 1 Obj -9053.03 Unsat 1 depth 1
Cbc0016I Integer solution of -8884.54 found by strong branching after 4 iterations and 2 nodes (0.00 seconds)
Cbc0015I Node 2 Obj -9053.03 Unsat 1 depth 2
Cbc0014I Cut generator 0 (Probing) - 0 row cuts, 3 column cuts (3 active)
Cbc0001I Search completed - best objective -8884.536585365899, took 35 iterations and 6 nodes (0.00 seconds)
Cbc0032I Strong branching done 4 times (9 iterations), fathomed 0 nodes and fixed 0 variables
Cbc0035I Maximum depth 2, 0 variables fixed on reduced cost
Cbc0029I Ending sub-tree for CbcHeuristicFpump
Cbc0038I Cleaned solution of -8884.54
Cbc0038I Before mini branch and bound, 19 integers at bound fixed and 0 continuous
Cbc0038I Mini branch and bound improved solution from -8884.54 to -8884.54 (0.01 seconds)
Cbc0038I Round again with cutoff of -8908.14
Cbc0038I Reduced cost fixing fixed 4 variables on major pass 2
Cbc0038I Solution found of -9120.53
Cbc0038I Branch and bound needed to clear up 1 general integers
Cgl0009I 1 elements changed
Cgl0009I 1 elements changed
Cgl0004I processed model has 3 rows, 5 columns (5 integer) and 12 elements
Cbc0038I Full problem 7 rows 20 columns, reduced to 3 rows 5 columns
Cbc0028I Starting sub-tree for CbcHeuristicFpump - maximum nodes 200
Cbc0013I At root node, 0 cuts changed objective from -9120.53 to -9053.03 in 2 passes
Cbc0014I Cut generator 0 (Probing) - 0 row cuts, 2 column cuts (2 active)
Cbc0010I After 0 nodes, 1 on tree, 1e+50 best solution, best possible -9053.03 (0.00 seconds)
Cbc0015I Node 1 Obj -9053.03 Unsat 1 depth 1
Killed

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