Same problem working with IPOPT but failing with BONMIN

[Sourav Mondal]

Hi

I am trying to solve a mixed-integer non-linear programming problem by using BONMIN package through AMPL platform. The objective function is linear and have several other linear constraints. Only one constraint is non-linear but it is twice or more differentiable. When I tried to solve it using IPOPT solver by issuing the following commands, it works but doesn't produce an integer optimal solution, as expected.

model hyb_cld.mod;
data hyb_cld.dat;
option solver ipopt;
option ipopt_options "linear_solver Pardiso";

However, when I am using the BONMIN solver next, the solver is halting with the following output.

model hyb_cld.mod;
data hyb_cld.dat;
option solver bonmin;

Bonmin 1.8.4 using Cbc 2.9.7 and Ipopt 3.12.4

******************************************************************************

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

******************************************************************************

NLP0012I 

              Num      Status      Obj             It       time                 Location

NLP0014I             1      FAILED 583.30161        1 22.484

NLP0014I             1      FAILED 583.30161        1 22.216   resolve robustness

NLP0014I             3      FAILED 583.30161        1 21.167                      totot

Cbc0006I The LP relaxation is infeasible or too expensive

  "Finished"

bonmin: Infeasible problem

Can anyone please help me in finding a way out from this situation? Do I need to change any particular option for the solver?

Thanks in advance.

Regards,

Sourav

[Robert Fourer]

Bonmin messages ending in "I" are informational and do not necessarily imply that there was an error. At the end of your run, Bonmin reports "Infeasible problem" so there may not be any solution to your constraints (with integer values of the variables). For more help however you will need to contact the Bonmin project; see the COIN-OR Bonmin page at https://www.coin-or.org/Bonmin/.

Bob Fourer
am...@googlegroups.com

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