[Osi] CPLEX Error 1217: No solution exists

[Matthew Galati]

Umm... ok, header has pure (=0) but src has it implemented. Bug.

> It looks to me like base implementation is pure virtual
>     /// Get objective function value
>     virtual double getObjValue() const = 0;
>
>
>   
>> CPLEX wipes out all solution information as soon as you make any 
>> change to the problem whatsoever. I don't believe that the objective 
>> value is one of the things cached in the base class. If you look at 
>> the current implementation of getObjVal() in OsiCpx, it tries to get 
>> the objective value using CPXgetobjval(). If Cplex reports 
>> CPXERR_NO_SOLN, then the function returns 0.0 by default. In the base 
>> class, the default implementation of the getObjVal() function computes 
>> the objective value on the fly from cached data, which I guess would 
>> fix the problem. Try just commenting out the getObjVal() function in 
>> OsiCpx or else call the base class implementation from there and see 
>> if that does what you need.  If that works, we should probably make 
>> that change.
>>
>> Cheers,
>>
>> Ted
>>
>>
>>
>> Matthew Galati wrote:
>>     
>>> This might be related to an old discussion...
>>>
>>> Using OsiCpx, I do
>>>   initialSolve()
>>>   getObjValue()
>>>   addCols()
>>>   getObjValue()  --> returns CPLEX Error  1217: No solution exists
>>>
>>> This is just an LP. Earlier issues with caching seem to have to do 
>>> with switching from MIP to LP, etc.
>>>
>>> It looks like some attempt to keep cache was already made. Any ideas? 
>>> If needed, I can create a driver program to show this issue.
>>>
>>> int err = CPXaddcols(env_, 
>>> getLpPtr(OsiCpxSolverInterface::KEEPCACHED_ROW),
>>>                       numcols, nz, const_cast<double*>(obj),
>>>                       start, index, elem,
>>>                       const_cast<double*>(collb),
>>>                       const_cast<double*>(colub), NULL );
>>>
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>>     
>
>
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