[Coin-lpsolver] MPS output problem detected

[John J Forrest]

It is not an error in MPS output but an error (been there for several 
years) on converting a network matrix to a standard CoinPackedMatrix 
format.  In Clp every matrix type must be able to return a matrix as a 
CoinPackedMatrix.  With a network matrix doing MPS output was the most 
likely time to do this - but somehow it had never been tested.

Seems to be fixed now.

Thanks for finding the bug.

John Forrest



"Lijian Chen" <lijian.chen at louisville.edu> 
Sent by: coin-lpsolver-bounces at list.coin-or.org
02/27/2007 05:47 PM

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<coin-lpsolver at list.coin-or.org>
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Subject
[Coin-lpsolver] MPS output problem detected






Dear Folks,

I realized there might be an issue discovered by my experience.

Since I am a newbie moving to open source code, I use examples to gain 
experience. What I did was

add "#include<CoinMpsIO.hpp>" into the source code of network.cpp

add "model.writeMps("test.mps");" into the body of network.cpp

Then I use "make DRIVER=network" to build the binary.

Till now, everything is fine. I want to use my old friend, xpress_MP to 
test the solution. It takes more than a hour to analyze infeasibility. I 
ran out of patience and I try to use Clp to test mps file. 

However, when I input the "./clp test.mps", I got the following error 
message,

Coin LP version 1.03.03, build Feb  8 2007
command line - ./clp /home/lijian/success/workspace/birge_book/test.mps
At line 1 NAME          BLANK
At line 2 ROWS
At line 5004 COLUMNS
Duplicate row R0000223 at line 26280 <     C0010637  R0000223   -1. >
At line 30005 RHS
At line 30506 BOUNDS
At line 43007 ENDATA
Problem BLANK has 5000 rows, 12500 columns and 24999 elements
 There were 1 errors when importing model from 
/home/lijian/success/workspace/birge_book/test.mps
There were 1 errors on input

Can anyone tell me why? I am working on research of stochastic 
programming. I want to make sure my code would reflect my algorithm 
accurately. Thanks!


Lijian Chen

Assistant Professor
J.B. Speed School of Engineering
Department of Industrial Engineering
University of Louisville
(Tel) 502-852-2197
(Fax) 502-852-5633

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