[Bonmin] Feasibility in BONMIN
Stefan Vigerske
stefan at math.hu-berlin.de
Wed Jul 31 08:07:20 EDT 2013
Hi,
On 07/31/2013 01:47 PM, Novalio Daratha wrote:
> Dear All,
>
> I am trying to solve an MINLP using bonmin. It reported the MINLP as
> infeasible problem while during the iterations I see some feasible
> solutions.
These are solutions of the NLP relaxation (with reduced bounds on some
discrete variables), they are not necessarily feasible for the MINLP, too.
> My question are:
>
> 1. why does bonmin conclude it as infeasible problem?
It could not find a feasible point and investigated all nodes of the
branch-and-bound tree.
> 2. why not it gives the feasible solution even if it is not locally
> optimal?
It does not have one.
Stefan
>
> For your consideration, I put an example of bonmin output at the end of
> this email. (bb_log_level 1).
>
>
> I am thankful for your kind attention and help.
>
> Sincerely Yours,
>
> Novalio Daratha
> PhD student
> IIT Roorkee
> India
>
>
>
> Bonmin 1.5.2 using Cbc 2.7.6 and Ipopt 3.10.2
> bonmin:
>
> ******************************************************************************
> This program contains Ipopt, a library for large-scale nonlinear
> optimization.
> Ipopt is released as open source code under the Eclipse Public License
> (EPL).
> For more information visit http://projects.coin-or.org/Ipopt
> ******************************************************************************
>
> NOTE: You are using Ipopt by default with the MUMPS linear solver.
> Other linear solvers might be more efficient (see Ipopt
> documentation).
>
>
> NLP0012I
> Num Status Obj It time
> Location
> NLP0014I 1 FAILED 0.0044821868 3000 8.388
> NLP0014I 1 FAILED 0.0044678956 3000 7.652 resolve
> robustness
> NLP0014I 3 OPT 0.0041219542 1030 3.17
> NLP0012I
> Num Status Obj It time
> Location
> NLP0014I 1 INFEAS 1 54 0.144
> NLP0014I 4 FAILED 1.2200549 3000 7.826
> NLP0014I 5 FAILED 1.2400101 3000 8.146
> NLP0014I 6 FAILED 1.2413622 3000 8.007
> NLP0014I 7 FAILED 1.2398611 3000 7.769
> NLP0014I 8 FAILED 0.03787479 3000 7.779
> NLP0014I 9 FAILED -0.070294006 3000 7.33
> NLP0014I 10 FAILED 0.0044563366 3000 7.775
> NLP0014I 11 FAILED -0.070344772 3000 7.33
> NLP0014I 12 FAILED 1.2242858 3000 7.964
> NLP0014I 13 FAILED -0.070401127 3000 7.064
> NLP0014I 14 FAILED 1.2470022 3000 7.639
> NLP0014I 15 FAILED -0.070728211 3000 6.996
> NLP0014I 16 OPT 0.0041219556 945 2.374
> NLP0014I 17 FAILED -0.070781423 3000 6.949
> NLP0014I 18 FAILED 0.0044845077 3000 7.292
> NLP0014I 19 FAILED -0.069781992 3000 7.329
> NLP0014I 20 FAILED 0.0045109264 3000 7.359
> NLP0012I
> Num Status Obj It time
> Location
> NLP0014I 21 FAILED -0.070408086 3000 7.094
> NLP0014I 22 FAILED 0.0045273783 3000 7.419
> NLP0014I 23 FAILED -0.070202589 3000 7.304
> NLP0014I 24 FAILED 0.0054378863 3000 7.413
> NLP0014I 25 FAILED -0.068064574 3000 7.261
> NLP0014I 26 OPT 0.0041219556 6 0.012
> NLP0014I 27 INFEAS 0.022268486 32 0.074
> NLP0014I 28 OPT 0.0041219556 6 0.012
> NLP0014I 29 FAILED 1.241151 3000 7.391
> NLP0014I 30 FAILED 0.018211754 3000 7.548
> NLP0014I 31 OPT 0.0041219556 803 1.956
> NLP0014I 32 FAILED -0.15280958 3000 7.369
> NLP0014I 33 OPT 0.0041219545 9 0.03
> NLP0014I 34 FAILED -0.07020253 3000 7.219
> NLP0014I 35 OPT 0.0041219549 7 0.022
> NLP0014I 36 FAILED -0.069945526 3000 7.181
> NLP0014I 37 OPT 0.0041219552 11 0.038
> NLP0014I 38 FAILED -0.070313109 3000 7.356
> NLP0014I 39 OPT 0.0041219556 14 0.031
> NLP0014I 40 FAILED -0.070260101 3000 7.076
> NLP0012I
> Num Status Obj It time
> Location
> NLP0014I 41 OPT 0.0041219556 7 0.016
> NLP0014I 42 FAILED -0.070746826 3000 7.126
> NLP0014I 43 OPT 0.0041219556 6 0.013
> NLP0014I 44 FAILED -0.070402666 3000 7.196
> NLP0014I 45 OPT 0.0041219556 6 0.013
> NLP0014I 46 FAILED -0.070522355 3000 7.377
> NLP0014I 47 OPT 0.0041219556 6 0.013
> NLP0014I 48 FAILED -0.069211894 3000 7.122
> NLP0014I 49 OPT 0.0041219556 6 0.012
> NLP0014I 50 FAILED -0.053808856 3000 6.91
> NLP0014I 51 OPT 0.0041219556 6 0.013
> NLP0014I 52 INFEAS 0.016728388 36 0.086
> NLP0014I 53 OPT 0.0041219556 6 0.013
> NLP0014I 54 FAILED 1.2291456 3000 7.679
> NLP0014I 55 FAILED 0.0045429683 3000 7.632
> NLP0014I 56 OPT 0.0041219556 6 0.013
> NLP0014I 57 INFEAS 0.010787243 32 0.075
> NLP0014I 58 OPT 0.0041219556 6 0.013
> NLP0014I 59 FAILED 1.1645369 3000 8.174
> NLP0014I 60 FAILED 0.0063708004 3000 7.581
> NLP0012I
> Num Status Obj It time
> Location
> NLP0014I 61 OPT 0.0041219492 20 0.062
> NLP0014I 62 INFEAS 0.0046434659 38 0.089
> NLP0014I 63 OPT 0.0041219492 20 0.063
> NLP0014I 64 INFEAS 0.99998118 703 1.888
> NLP0014I 65 FAILED 1.2612585 3000 8.095
> NLP0014I 66 FAILED 1.2456221 3000 7.746
> Cbc0001I Search completed - best objective 1e+050, took 3038 iterations and
> 0 nodes (299.17 seconds)
> Cbc0032I Strong branching done 29 times (116699 iterations), fathomed 0
> nodes and fixed 5 variables
> Cbc0035I Maximum depth 0, 0 variables fixed on reduced cost
> NLP0014I 67 FAILED -0.14257739 3000 7.17
>
> "Finished"
>
> bonmin: Infeasible problem
>
>
>
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