[Coin-discuss] Strange termination

[Matthew Saltzman]

On Fri, 17 Jun 2005, Kasper Bonne Rasmussen wrote:

> On Fri, 17 Jun 2005, Ted Ralphs wrote:
>> There is probably a problem status that is not being checked for. I
>> suggest printing out the problem status at the end of the
>> branchAndBound() method using
>>
>> CPXgetstat( env_, getMutableLpPtr() );
>>
>> and see what it is when this happens. Check the CPLEX header file to see
>> what the status means and then check the OSI status query methods to see
>> if any of them check for that particular status. If not, there's a
>> problem.  This should narrow down the problem, so we can make the
>> appropriate change to the code.
>
> CPXgetstat(env_, getMutableLpPtr()) returns 119 in the call that fails to
> generate an optimal solution. cplex.h defines 119 as
> CPXMIP_NODE_FILE_LIM_INFEAS. None of the query methods check for that.
>
> ...but what exactly does it mean? I happens in relatively small problems
> <500 columns.


What version of CPLEX are we talking about here?

Since at least CPLEX 8.1, code 119 is CPX_MIP_INForUNBD.

CPXMIP_NODE_LIM_INFEAS (code 106) means the limit on the number of nodes 
was encountered without finding an integer feasible solution.  There are 
some CPXMIP_FAIL_... codes, but no CPXMIP_FILE_... codes.

>
> /Kasper
>
>
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-- 
 		Matthew Saltzman

Clemson University Math Sciences
mjs AT clemson DOT edu
http://www.math.clemson.edu/~mjs