[Coin-discuss] integer column bounds fixed by CBC/CLP?
John J Forrest
jjforre at us.ibm.com
Wed Jun 28 04:00:48 EDT 2006
a) Yes the MIP can add more rows during Branch and Cut - these will be at
b) If you use CglPreProcess it has methods originalRows and originalColumns
which point back while the problem is preprocessed - after postprocessing
these will just be 0,1,2.
<kish.shen at crossc
Sent by: coin-discuss at list.coin-or.org
ces at list.coin-or.
Re: [Coin-discuss] integer column
bounds fixed by CBC/CLP?
06/27/06 11:12 PM
Please respond to
<coin-discuss at lis
On Sunday 25 June 2006 11:36, John J Forrest wrote:
> This was deliberate so that further processing could be done. Even if
> reset bounds then some information has been modified e.g. best solution.
> Suggested way of doing repeated runs is as in Cbc/examples/repeat.cpp and
> also see references to referenceSolver in CbcModel.hpp
> John Forrest
John, thanks for your quick reply!
I have updated my code so that it saves a reference solver just before
the MIP, and then after the solve, extract the required solution
(variable solution values, reduced costs, etc.), and then reset to the
Am I correct in that the MIP can add extra rows to the problem by posting
cuts to the problem? Also, can the presolve remove columns/rows from the
problem? Are these changes visible in the model after the solving? CPLEX
XPRESS allows the user to extra information from the probelm using the
original rows/column numbers, and this is important for our usage, as they
map to the user's variables and constraints.
Coin-discuss mailing list
Coin-discuss at list.coin-or.org
More information about the Coin-discuss