Opened 13 years ago

Closed 13 years ago

Last modified 13 years ago

#2 closed defect (fixed)

Problem with different interfaces for Bonmin and Ipopt function get_starting_point

Reported by: phines Owned by: pbonami
Priority: minor Component: component1
Version: Keywords:

Description (last modified by pbonami)

I am using Bonmin to perform mixed integer optimization, but I wanted to check my derivatives with Ipopt. Ipopt and Bonmin have slightly different interfaces for the function get_starting_point. When I had the Bonmin convection implemented (does not use init_z), but not the Ipopt one, Ipopt will call get_bounds_info(...) instead of get_starting_point(...). This is VERY confusing. I spent 2 days trying to figure out why the inputs to get_bounds_info were strange, and why I kept getting segmentation faults.

I would recommend that the two interfaces be reconciled, so that this type of error could be avoided in the future.

thanks, -paul

Attachments (2)

MyTMINLP.cpp (3.8 KB) - added by phines 13 years ago.
MyTMINLP.hpp (8.1 KB) - added by phines 13 years ago.

Download all attachments as: .zip

Change History (6)

comment:1 Changed 13 years ago by pbonami

  • Owner changed from somebody to pbonami
  • Status changed from new to assigned

I am sorry I did not notice this inconsistency before and you spent two days on this. The function get_bounds_info of TMINLP and TNLP are coherent now (both have init_z).

For Ipopt calling get_bounds_info instead of get_starting_point, I don't understand it well. These two functions returns different things, one will return the values of the bounds on the variable (get_bounds_info...), the other returns initial values for the multipliers of the simple bounding constraints on the variables.

Paul, if the changes I made do not totally fix it, could you please be more specific on the second point. Thanks, Pierre

Changed 13 years ago by phines

Changed 13 years ago by phines

comment:2 Changed 13 years ago by phines

Thank you. The change made the CppExample? (MyTMINLP) not work. I fixed this and submitted the change in the two attached files.

Thanks, -paul

comment:3 Changed 13 years ago by pbonami

  • Description modified (diff)
  • Resolution set to fixed
  • Status changed from assigned to closed

comment:4 Changed 13 years ago by pbonami

  • Description modified (diff)
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