[Cbc] Newbie question about use of CBC and how to specify integraly constraints?

Thu Mar 17 11:34:12 EDT 2016

 I did copy/paste of the last problem from the link CPLEX LP file format to the file and I tried to run cbc against this file but the cbc crashed. I also tried to run cbc against valid *.lp file (which is made by lpsolve and is recognized by lpsolve) but cbc crashed again. From my experience cbc accepts mps files only. Is there some test cplex lp file available?

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| CPLEX LP file formatThe CPLEX LP file format provides a facility for entering a problem in a natural, algebraic LP formulation from the keyboard. The problem can be modified and saved from within lpsolve. This procedure is one way to create a file in a format that lpsolve can read. An alternative tec... |
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| Se på lpsolve.sourceforge.net | Forhåndsvis efter Yahoo |
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    Den 17:17 torsdag den 17. marts 2016 skrev Haroldo Gambini Santos <haroldo.santos at gmail.com>:

  Hi Jonatan,

 CBC also loads problems in the CPLEX LP file format, which is much simpler in my opinion.  (http://lpsolve.sourceforge.net/5.0/CPLEX-format.htm)

 To load a problem in LP format and save a solution in a TXT file just call:

 cbc  problem.lp  solve  solu  solution.txt

 Cheers,

 Haroldo

 On 17-03-2016 10:31, Jonatan Knud Lauritsen wrote:

  Regarding use of cbc. I understand that problem can be loaded and saved from and to MPS file using commands import and export. But what are commands for displaying and exporting to file the results of optimization, specifically - the values of variables? 

      Den 15:25 torsdag den 17. marts 2016 skrev Jonatan Knud Lauritsen <jonatan.lauritsen at yahoo.dk>:

    Hi!     
  I am starting to use CBC. I need integer linear programming solver and apparently CBC is the right software from the COIN-OR projects (I am not sure about  Symphony project, maybe it can solve integer linear programs as well). I am confused how to use CBC. I expected cbc.dll, but there is only cbc.exe available.  I am trying to use cbc.exe, I managed to import and solve problem but I don't understand how to get results back - e.g. how to see (and save to file)  values of the variables? That is the first question. 
  The second question is - is there cbc.dll available? I found  CoinMP.dll and tried to use it, but it seems to me an completely incomplete project. E.g. after  importing and preparing problems, the getColCount and getRowCount returns zero values. One can see in the source code that lot of methodes simply  return dummy value and does nothing. So - how CBC is intended to use? My impression is that CBC is simple collection of source files and one should  combine, integrate them and build them as one needes, there is no ready dll (apart from  cbc.exe, which is not quite suitable to be embedded in other software as it works as interactive session and not as input-output program). 
  The third question is about mps file format which I am using. How to  specify integrality constraints on variables in this file format? Maybe cbc automatically  assumes that all the unkown variables will be integers? wikipedia mentions that MPS extensions are suitable for specifying integrality  constraints but do CBC supports such extensions and where they ar documented? 
  Thanks in advance!

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Haroldo Gambini Santos
D.Sc, Computer Science
Universidade Federal de Ouro Preto
http://www.decom.ufop.br/haroldo/ 

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