[Symphony] Issue: get No solution in Symphony

[Menal Guzelsoy]

Can you send us the problem in LP or MPS format?

Menal Guzelsoy
1610 4620455



On Mon, Mar 28, 2011 at 1:11 PM, Vladyslav Kolbasin <marcell at insart.com> wrote:
>
> 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.
>
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