Hi I have a very large cplex model and it is feasible but when i am solving it using cplex I am getting no solution immediately after presolve.

Aggregator has done 1 substitutions...
Aggregator has done 17701 substitutions...
Aggregator has done 35801 substitutions...
Aggregator has done 54701 substitutions...
Aggregator has done 74201 substitutions...
Aggregator has done 94401 substitutions...
Aggregator has done 115501 substitutions...
Aggregator has done 137501 substitutions...
Aggregator has done 160701 substitutions...
Aggregator has done 185101 substitutions...
Aggregator has done 211101 substitutions...
Aggregator has done 239001 substitutions...
Aggregator has done 269001 substitutions...
Aggregator has done 302001 substitutions...
Aggregator has done 339201 substitutions...
Aggregator has done 382401 substitutions...
Presolve time = 188.63 sec. (165051.19 ticks)

Root node processing (before b&c):
Real time = 213.09 sec. (167412.54 ticks)
Parallel b&c, 32 threads:
Real time = 0.00 sec. (0.00 ticks)
Sync time (average) = 0.00 sec.
Wait time (average) = 0.00 sec.
------------
Total (root+branch&cut) = 213.09 sec. (167412.54 ticks)
Solution status = Unknown No Solution

It does not mention any constraint being infeasible. Solution status is unknown. There is no time limit set for the model so time can not be an issue. Can you please tell me what could be the reason.

Thank you Meghna

asked 15 Dec '14, 01:45

Meghna's gravatar image

Meghna
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accept rate: 0%

edited 15 Dec '14, 02:56

Are you using the interactive solver or one of the APIs? If an API, which? Also, what happens if you disable presolve and then try the problem?

(19 Dec '14, 16:00) Paul Rubin ♦♦

Post your question on the IBM CPLEX forum at https://www.ibm.com/developerworks/community/forums/html/forum?id=11111111-0000-0000-0000-000000002059 , where you have a better chance of getting a CPLEX expert to respond.

link

answered 19 Dec '14, 22:15

Mark%20L%20Stone's gravatar image

Mark L Stone
447310
accept rate: 15%

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Asked: 15 Dec '14, 01:45

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Last updated: 19 Dec '14, 22:15

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