[Cbc-tickets] [COIN-OR Branch-and-Cut MIP Solver] #20: bugs in cbc (command interface)

[COIN-OR Branch-and-Cut MIP Solver]

#20: bugs in cbc (command interface)
--------------------------------+-------------------------------------------
 Reporter:  matteo.fischetti    |       Owner:  somebody  
     Type:  defect              |      Status:  new       
 Priority:  major               |   Milestone:  milestone1
Component:  component1          |     Version:  1.0       
 Keywords:  memory leak in cbc  |  
--------------------------------+-------------------------------------------
 I posted at

 www.dei.unipd.it/~fisch/bugs.zip

 3 cases where cbc gets stuck before entering the FP heuristic and the
 branching phase: just run the 3 batch files in the zip file.

 Instances bug1 and bug3 are similar and get stuck here:

 ...
 Initial range of elements is 1 to 100
 Final range of elements is 0.302821 to 3.30228
 Absolute values of scaled rhs range from 0.7897 to 1448, minimum gap
 1e+100
 Absolute values of scaled objective range from 4794.78 to 3.30228e+009
 Absolute values of scaled bounds range from 0.277688 to 156.122, minimum
 gap 0.277688
 <-- no more output

 whereas instance bug2 has problems in the strengthening phase and ends
 with a crash (memory leak?)

 Optimal - objective value 2.30089e+010
 Coin0506I Presolve 940 (-914) rows, 7887 (-1419) columns and 97967
 (-18829) element
 s
 Cgl0003I 459 fixed, 2871 tightened bounds, 2 strengthened rows, 0
 substitutions
 Cgl0003I 459 fixed, 0 tightened bounds, 2 strengthened rows, 0
 substitutions
 Cgl0003I 82 fixed, 1852 tightened bounds, 6 strengthened rows, 0
 substitutions
 Cgl0003I 0 fixed, 0 tightened bounds, 6 strengthened rows, 0 substitutions
 Cgl0003I 9 fixed, 447 tightened bounds, 6 strengthened rows, 0
 substitutions
 Cgl0003I 0 fixed, 0 tightened bounds, 6 strengthened rows, 0 substitutions
 Cgl0003I 32 fixed, 58 tightened bounds, 6 strengthened rows, 0
 substitutions
 Cgl0003I 11 fixed, 44 tightened bounds, 6 strengthened rows, 0
 substitutions
 Cgl0003I 0 fixed, 0 tightened bounds, 6 strengthened rows, 0 substitutions
 Cgl0003I 1 fixed, 0 tightened bounds, 6 strengthened rows, 0 substitutions
 Cgl0003I 0 fixed, 0 tightened bounds, 6 strengthened rows, 0 substitutions
 Cgl0003I 345 fixed, 3484 tightened bounds, 7 strengthened rows, 0
 substitutions
 Cgl0003I 0 fixed, 0 tightened bounds, 7 strengthened rows, 0 substitutions
 Cgl0003I 0 fixed, 0 tightened bounds, 7 strengthened rows, 0 substitutions
 Cgl0003I 0 fixed, 0 tightened bounds, 7 strengthened rows, 0 substitutions
 Cgl0003I 0 fixed, 0 tightened bounds, 7 strengthened rows, 0 substitutions
 <-- crash

 Thanks

 --Matteo Fischetti--

 p.s. can I skip the (often time consuming)tightened phase

 Cgl0003I 459 fixed, 2871 tightened bounds, 2 strengthened rows, 0
 substitutions

 by just specifing a parameter in the command-line cbc.exe?

 p.s.2 is someone aware of a version of the command-interface that can be
 invoked as a function by a calling program, by passing the argument string
 "-import ..."? This could be useful as a quick shot to use cbc in its
 "command interface" implementation, which peforms quite well indeed.
 Allowing .lp input files would also help. I started working on it but I
 still have some memory leaks.

-- 
Ticket URL: <https://projects.coin-or.org/Cbc/ticket/20>
COIN-OR Branch-and-Cut MIP Solver <http://projects.coin-or.org/Cbc>
An LP-based branch-and-cut MIP solver.