[Symphony] Issue: get No solution in Symphony

[Vladyslav Kolbasin]

No i didn't set common bounds (upper_bound & lower_bound or
..._bound_estimate)

I tryed to set them (upper_bound & lower_bound) in wide range - nothing
changed and i still have NO_SOLUTION


Thanks a lot.

On Mon, 28 Mar 2011 11:32:14 -0400, Ted Ralphs <tkralphs at Lehigh.EDU>
wrote:
> If you would be so kind as the post your inquiry to the mailing list,
> we will try to get you an answer. Fomr the output, it looks as thought
> you must be setting an a priori upper bound and the solver is not able
> to imprve on that.
> 
> Cheers,
> 
> Ted
> 
> On Mon, Mar 28, 2011 at 11:29 AM, Vladyslav Kolbasin
> <marcell at insart.com> wrote:
>>
>>
>> Good Day!
>>
>>   I'm using RSymphony (package that uses Symphony for R).
>>   I'm running rather large LP problems : about 1000-3000 variables and
>> 800-2000 constraints.
>>
>>   For some my test-cases i get return code 226 (NO_SOLUTION). But i know
>> that there are simple solutions and may be rather complex too.
>>
>>   I set param verbosity to 140 and get such return:
>>
>>
>>
>> Skipping Preprocessor
>> Problem has
>>          834 constraints
>>          1065 variables
>>          4366 nonzero coefficients
>>
>> Solving...
>>
>> granularity set at 0.000001
>>
>> TM: tree size: 0 , 0
>>
>> ****************************************************
>> * Now processing NODE 0 LEVEL 0 (from TM)
>> ****************************************************
>>
>> Diving set to 2
>>
>>
>>
>> **** Starting iteration 1 ****
>>
>> solving root lp relaxation
>> Terminating due to high cost -- fathoming node (no more cols to check)
>>
>>
>> ****************************************************
>> * Branch and Cut Finished                          *
>> * Now displaying stats and best solution found...  *
>> ****************************************************
>> .....
>>
>>
>>
>>
>>
>>   Also if i do some mixing constraints & variables then get solution - it is
>> most strange issue.
>>
>>
>>
>>   Please Can you help me:
>> - explain why i can't get solution
>> - advise any params (or may be combination) that can help me to get any
>> solution (already tryed some from "LP parameters" and some others)
>>
>> Thanks a lot.