Running cbc on the attached problem multiple times with threads set to the number of cores produces different results. All cuts, heuristics and preprocessing are turned off. Attached is a script which runs the problem repeatedly until it finds a discrepancy. Removing the threads option produces the same right answer when rerun. I've configured cbc using the --enable-cbc-parallel, --disable-shared and --enable-static flags. I've tried different versions of cbc (2.8 and 2.8.9) and the issue is reproducible with all of them. Tested on Ubuntu 12.04.
Attachments: https://github.com/s-c-e/cbc-trac-migration-attachments/blob/master/trac-ticket-147.zip
Running cbc on the attached problem multiple times with threads set to the number of cores produces different results. All cuts, heuristics and preprocessing are turned off. Attached is a script which runs the problem repeatedly until it finds a discrepancy. Removing the threads option produces the same right answer when rerun. I've configured cbc using the --enable-cbc-parallel, --disable-shared and --enable-static flags. I've tried different versions of cbc (2.8 and 2.8.9) and the issue is reproducible with all of them. Tested on Ubuntu 12.04.