[Coin-lpsolver] Segmentation fault

[John J Forrest]

Brad,

If you get such a message then you should do exactly what you did do.  It
may not always be possible to reproduce the error... but in this case it
was possible.

That problem (with maximization) could be declared primal infeasible or
primal unbounded.  In both cases you want a ray returned to the user - in
the first case of length number rows, in the second case length number
columns.  Clp thought it was unbounded but changed its mind at the last
minute and so thought it had a ray of length number rows when in fact it
was only number columns long (number rows > number columns).

Should be fixed now (but not on NEOS server).

John Forrest


                                                                           
             Brad Bell                                                     
             <bradbell at apl.was                                             
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                                       [Coin-lpsolver] Segmentation fault  
                                                                           
             07/30/06 02:49 PM                                             
                                                                           
                                                                           
                                                                           
                                                                           





It appears from the message below that the CLP executable had a a
segmentation fault while running a problem that I submitted. What should a
Neos server Clp user do when they get this message ? (I am attaching the
submitted problem.)


---------- Forwarded message ----------
Date: Sun, 30 Jul 2006 13:36:12 -0500
From: neos at mcs.anl.gov
To: bradbell at apl.washington.edu
Subject: NEOS Results for Job #811784

You are using the solver clp-mps.

\%%%%%%%%%%%%%%%%%%%% CLP Results %%%%%%%%%%%%%%%%%%%%

Load Avg: ( 0.08 , 0.02 , 0.01 )
Coin LP version 1.02.02, build Mar 20 2006
command line - /home/neos/neos-bin/clp clp.mps -
At line 4 NAME          CE-2.1
At line 5 ROWS
At line 86 COLUMNS
At line 358 RHS
At line 371 ENDATA
Problem CE-2.1 has 72 rows, 48 columns and 187 elements
Model was imported from ./clp.mps in -6.60686e-19 seconds
Switching to line mode
Clp:Clp:Clp:/bin/sh: line 1: 13828 Segmentation fault      nice -15
/home/neos/neos-bin/clp clp.mps - <clp.par
 Error (35584) in /home/neos/neos-bin/clp clp.mps - < clp.par


%%%%%%%%%%%%%%%%%%%% CLP Results %%%%%%%%%%%%%%%%%%%%[attachment
"Chapter12" deleted by John J Forrest/Watson/IBM]
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