Couenne says "infeasible problem" when there is binary variables!

[svigerske]

Issue created by migration from Trac.

Original creator: Burcu

Original creation time: 2017-04-04 08:16:18

Assignee: @merraksh

Version:

CC: burcu.akyildiz@gmail.com

Dear All,

It is a nonlinear MIP model with continuous, binary and integer variables. When I try to solve it with couenne it says that it is infeasible. But I have already found an initial solution by hand that suits model. I am attaching this hand-made initial solution.

I just made a search through the net and found out that Couenne gave "infeasible solution" for other people's models when there are binary variables. I changed my binary variables to continious variables, and couenne works! But ofcourse the result is meaningless. Would you please help me to solve the model with my binar variables?

I am attaching the model and data in AMPL format. Below you can see the result page, when I run the model with binary variables. Thank you!

ampl: model C:\Users\BURCU\Desktop\Tez\AMPL_TEZ\Facility-baFN4.mod; data C:\Users\BURCU\Desktop\Tez\AMPL_TEZ\Facility-baFN4.dat; solve; Couenne 0.5.6 -- an Open-Source solver for Mixed Integer Nonlinear Optimization Mailing list: couenne@list.coin-or.org Instructions: http://www.coin-or.org/Couenne couenne: ANALYSIS TEST: Reformulating problem: 0.5 seconds NLP0012I Num Status Obj It time Location NLP0014I 1 INFEAS 0.96000003 70 60.098 Loaded instance "C:\Users\BURCU\AppData\Local\Temp\at7600.nl" Constraints: 3796 Variables: 2271 (1121 integer) Auxiliaries: 1474 (287 integer)

Coin0506I Presolve 73 (-3599) rows, 78 (-3667) columns and 261 (-10185) elements Clp0006I 0 Obj 0 Primal inf 15608 (32) Clp0006I 33 Obj 3.0982e-014 Primal inf 2.999994 (6) Clp0006I 35 Obj 3.0988e-014 Clp0000I Optimal - objective value 0 Clp0032I Optimal objective 0 - 35 iterations time 0.032, Presolve 0.02 Clp0000I Optimal - objective value 0 NLP Heuristic: NLP0014I 2 INFEAS 0.99999999 32 1.229 no solution. Clp0000I Optimal - objective value 0 Optimality Based BT: 3 improved bounds Probing: 23 improved bounds NLP Heuristic: time limit reached. Cbc0013I At root node, 0 cuts changed objective from 0 to 0 in 1 passes Cbc0014I Cut generator 0 (Couenne convexifier cuts) - 0 row cuts average 0.0 elements, 57 column cuts (57 active) Cbc0010I After 0 nodes, 1 on tree, 1e+050 best solution, best possible -1.7976931e+308 (22.91 seconds) Optimality Based BT: 0 improved bounds Optimality Based BT: 0 improved bounds Optimality Based BT: 0 improved bounds Optimality Based BT: 0 improved bounds Cbc0001I Search completed - best objective 1e+050, took 298 iterations and 62 nodes (164.06 seconds) Cbc0035I Maximum depth 10, 0 variables fixed on reduced cost

"Finished"

Linearization cuts added at root node: 3672 Linearization cuts added in total: 3672 (separation time: 0.016s) Total solve time: 164.125s (164.125s in branch-and-bound) Lower bound: -inf Upper bound: inf (gap: --) Branch-and-bound nodes: 62 Performance of FBBT: 0.266s, 64 runs. fix: 0 shrnk: 0.826375 ubd: 7.02954 2ubd: 2.46442 infeas: 24

couenne: Infeasible problem

[svigerske]

Attachment [Facility hand-solution.xlsx](https://www.coin-or.org/issue-attachments/Couenne/ticket38/Facility hand-solution.xlsx) by Burcu created at 2017-04-04 08:16:50

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Attachment [Facility hand-solution.2.xlsx](https://www.coin-or.org/issue-attachments/Couenne/ticket38/Facility hand-solution.2.xlsx) by Burcu created at 2017-04-04 08:17:02

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Attachment Facility-hand-solution.jpg by Burcu created at 2017-04-04 08:17:41

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Attachment Facility-baFN4.dat by Burcu created at 2017-04-04 08:18:05

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Attachment Facility-baFN4.mod by Burcu created at 2017-04-04 08:19:49