Opened 5 years ago

Closed 7 weeks ago

#151 closed defect (migrated)

quadratic objective with cbc

Reported by: godsend Owned by: tkr
Priority: major Component: Cbc
Version: 2.8 Keywords:
Cc:

Description

Hello,

I read that cbc can solve quadratic problem or I didn't understand.

At the page http://www.coin-or.org/Cbc/cbcuserguide.html, point 7, topic Quadratic MIP, it's written "it is possible to do quadratic MIP with CBC". furthermore, Cbc provide some quadratic problem exemples : quad.mps and quad2.mps with the keyword "QUADOBJ".

So, if I try to solve quad.mps I have some problems.

First case (result file : firstcase.txt) : I open cbc with shell and I import quad.mps


Coin:import quad.mps ... Coin:solve ... Result - Optimal solution found

Objective value: 27797.14684147 Enumerated nodes: 30530 Total iterations: 3410826 Time (CPU seconds): 208.77 Time (Wallclock seconds): 210.57


But if I want to print the result I have a segment fault :


Coin:solution solution.txt Erreur de segmentation (core dumped)


Second case (result file : secondcase.txt) : With a command line in the shell, I have no solution :


cbc quad.mps -solution stdout

Welcome to the CBC MILP Solver Version: 2.8 Build Date: May 7 2014 Revision Number: 2031

command line - cbc quad.mps -solution stdout (default strategy 1) At line 1 NAME At line 2 ROWS At line 299 COLUMNS At line 778 RHS At line 878 BOUNDS At line 985 QUADOBJ Problem no_name has 295 rows, 260 columns and 869 elements Coin0008I no_name read with 0 errors At line 1000 ENDATA Status unknown - objective value 0.00000000 Total time (CPU seconds): 0.00 (Wallclock seconds): 0.00


But if and don't ask the solution it seems to work but impossible to know the details of the solution. I added that Gurobi find different objective value (file : gurobi.txt) :


cbc quad.mps

Result - Optimal solution found

Objective value: 27797.14684147 Enumerated nodes: 30530 Total iterations: 3410826 Time (CPU seconds): 208.56 Time (Wallclock seconds): 211.71

Total time (CPU seconds): 208.56 (Wallclock seconds): 211.71


So, is it a bug ? Cbc can solve quadratic model ? Do you have any ideas ?

Thanks for your help and for your work. You provide very good products.

Attachments (3)

firstcase.txt (88.9 KB) - added by godsend 5 years ago.
secondcase.txt (88.8 KB) - added by godsend 5 years ago.
gurobi.txt (2.1 KB) - added by godsend 5 years ago.

Download all attachments as: .zip

Change History (4)

Changed 5 years ago by godsend

Changed 5 years ago by godsend

Changed 5 years ago by godsend

comment:1 Changed 7 weeks ago by stefan

  • Resolution set to migrated
  • Status changed from new to closed

This ticket has been migrated to GitHub and will be resolved there: https://github.com/coin-or/Cbc/issues/151

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