[Coin-discuss] Symphony's matching problem infeasible

[Michael Hennebry]

I tried to solve sample.mat with the match executable.
I was told, obviously incorrectly, that it was infeasible.

The problem seems to occur immediately.
The LP relaxation should give a minimum objective of 3, not 2.
sample.mat:
6
0 1 1 3 3 3
1 0 1 3 3 3
1 1 0 3 3 3
3 3 3 0 1 1
3 3 3 1 0 1
3 3 3 1 1 0

match output:
*******************************************************
*   This is SYMPHONY Version 5.0                      *
*   Copyright 2000-2004 Ted Ralphs                    *
*   All Rights Reserved.                              *
*   Distributed under the Common Public License 1.0   *
*******************************************************

SYMPHONY was called with the following arguments:
bin.LINUX/OSI_GLPK/match
-v 4
-F sample.mat

****************************************************
* Now processing NODE 0 LEVEL 0 (from TM)
****************************************************



**** Starting iteration 1 ****

The LP value is: 2.000 [2,4]

Feasibility lost -- fathoming node (no more cols to check)


****************************************************
* Branch and Cut Finished                          *
* Now displaying stats and best solution found...  *
****************************************************

====================== Misc Timing =========================
  Problem IO        0.000
  UB overhead:      0.000
  UB runtime:       0.000
  LB overhead:      0.000
  LB runtime:       0.000
====================== CP Timing =========================
  Cut Pool                  0.000
====================== LP/CG Timing =========================
  LP: Solution Time         0.000
      Variable Fixing       0.000
      Pricing               0.000
      Strong Branching      0.000
      Communication         0.000
      Idle Time (Node Pack) 0.000
      Idle Time (Nodes)     0.000
      Idle Time (Names)     0.000
      Idle Time (Diving)    0.000
      Idle Time (Cuts)      0.000
  Separation                0.000
  Total User Time              0.000
  Total Real Time              0.001

====================== Statistics =========================
Number of created nodes :       1
Number of analyzed nodes:       1
Depth of tree:                  0
Size of the tree:               1
Leaves before trimming:         0
Leaves after trimming:          0
Repriced root's nf_status:      NF_CHECK_ALL
Not fixed variable num:         0
Number of Chains:               1
Number of Diving Halts:         0
Number of cuts in cut pool:     0

No Solution Found


-- 
Mike   hennebry at web.cs.ndsu.NoDak.edu
"Our gods are dead.  Ancient Klingon warriors slew them
... they were more trouble than they were worth."          --  Worf