<br><font size=2 face="sans-serif">Probably this condition is due to an
unbounded ray being detected but no feasible solution has yet been found?
</font>
<br>
<br><font size=2 face="sans-serif">isAbandoned() might be the most appropriate
test in that case.</font>
<br>
<br><font size=2 face="sans-serif">Sounds like an interesting problem --
might be nice to have in the samples or for a regression test.<br>
</font>
<br><font size=2 face="sans-serif">Alan King</font>
<br>
<br>
<br>
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<td width=40%><font size=1 face="sans-serif"><b>Matthew Saltzman <mjs@ces.clemson.edu></b>
</font>
<br><font size=1 face="sans-serif">Sent by: coin-discuss-bounces@list.coin-or.org</font>
<p><font size=1 face="sans-serif">06/17/2005 01:08 PM</font>
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<div align=center><font size=1 face="sans-serif">Please respond to<br>
Discussions about open source software for Operations Research
<coin-discuss@list.coin-or.org></font></div></table>
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<div align=right><font size=1 face="sans-serif">To</font></div>
<td><font size=1 face="sans-serif">Discussions about open source software
for Operations Research <coin-discuss@list.coin-or.org></font>
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<td>
<div align=right><font size=1 face="sans-serif">cc</font></div>
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<div align=right><font size=1 face="sans-serif">Subject</font></div>
<td><font size=1 face="sans-serif">Re: [Coin-discuss] Strange termination</font></table>
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<br><font size=2><tt>On Fri, 17 Jun 2005, Kasper Bonne Rasmussen wrote:<br>
<br>
><br>
> On Fri, 17 Jun 2005, Matthew Saltzman wrote:<br>
>> On Fri, 17 Jun 2005, Kasper Bonne Rasmussen wrote:<br>
>>> CPXgetstat(env_, getMutableLpPtr()) returns 119 in the call
that fails to<br>
>>> generate an optimal solution. cplex.h defines 119 as<br>
>>> CPXMIP_NODE_FILE_LIM_INFEAS. None of the query methods check
for that.<br>
>><br>
>> What version of CPLEX are we talking about here?<br>
>><br>
>> Since at least CPLEX 8.1, code 119 is CPX_MIP_INForUNBD.<br>
><br>
> Cplex version 9.0 and you are absolutely right. I was looking in a<br>
> cplex-headerfile v7.0, sorry.<br>
><br>
> ..but there is still no query method that checks for this, as far
as I can<br>
> see.<br>
<br>
I'm not terribly surprised. But which of these should detect it?<br>
<br>
isAbandoned()<br>
isProvenOptimal()<br>
isProvenPrimalInfeasible()<br>
isProvenDualInfeasible()<br>
isPrimalObjectiveLimitReached()<br>
isDualObjectiveLimitReached()<br>
isIterationLimitReached()<br>
<br>
The docs are not clear what the circumstances are that lead to this return
<br>
code. There is a CPXMIP_UNBOUNDED (unbdd ray found) and a CPXMIP_INFEAS
<br>
(proven infeasible). So I will guess that CPXMIP_INForUNBD must arise
in <br>
some ambiguous case. We'd need to get CPLEX to weigh in on whether
the <br>
two cases are distinguishable with some additional calls.<br>
<br>
> /Kasper<br>
<br>
-- <br>
Matthew Saltzman<br>
<br>
Clemson University Math Sciences<br>
mjs AT clemson DOT edu<br>
http://www.math.clemson.edu/~mjs<br>
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</tt></font>
<br>