[Clp-tickets] [COIN-OR Linear Programming Solver] #15: Feasible
problem returns infeasible; inconsistent results
COIN-OR Linear Programming Solver
coin-trac at coin-or.org
Fri Nov 16 22:27:25 EST 2007
#15: Feasible problem returns infeasible; inconsistent results
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Reporter: ltaylor | Owner: somebody
Type: defect | Status: new
Priority: major | Milestone:
Component: component1 | Version:
Keywords: |
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This is an MPS file generated by COINMP.dll interface, after loading it by
API calls. Under COINOptimizeProblem, it returns problem infeasible.
I have also tested it with: (1) windows binary clp.exe, several versions;
(2) locally compiled MS Visual studio 2005 project in debug mode, with
project files in synch with the latest (Nov. 16. 2007) versions, and
several previous versions. Revision 1137.
{{{
Coin LP version 1.06.00, build Nov 16 2007
Clp takes input from arguments ( - switches to stdin)
Enter ? for list of commands or help
Clp:directory c://temp//
Clp:import ch108-prob1.mps
At line 1 NAME BLANK
At line 2 ROWS
At line 98 COLUMNS
At line 11210 RHS
At line 11211 BOUNDS
At line 13581 ENDATA
Problem BLANK has 94 rows, 2369 columns and 17942 elements
Model was imported from c://temp//\ch108-prob1.mps in 0.062 seconds
Clp:duals
Presolve 72 (-22) rows, 2323 (-46) columns and 17764 (-178) elements
0 Obj 0 Primal inf 31.3191 (16)
76 Obj 4.52447e-006 Primal inf 0.587574 (7)
152 Obj 0.207158 Primal inf 285148 (24)
156 Obj 0.220218 Primal inf 895508 (23)
215 Obj 8859.37 Primal inf 1.02777e+010 (24)
220 Obj 15623.2 Primal inf 2.32421e+010 (30)
220 Obj 15623.2 Primal inf 2.32421e+010 (30)
Primal infeasible - objective value 15623.2
Presolved problem not optimal, resolve after postsolve
After Postsolve, objective 15701.4, infeasibilities - dual 0.000231735
(1), prim
al 3.49235e+010 (51)
PrimalInfeasible objective 15701.42062 - 440 iterations time 0.232,
Presolve 0.0
9
Clp:
}}}
However, if I load the same file and use command 'primals', clp.exe
reports that the problem is feasible. As I know from solving it
previously, the correct solution has an objective of 4.87.
{{{
Microsoft Windows XP [Version 5.1.2600]
(C) Copyright 1985-2001 Microsoft Corp.
C:\Documents and Settings\Larry A. Taylor>cd my*
C:\Documents and Settings\Larry A. Taylor\My Documents>cd coi*
C:\Documents and Settings\Larry A. Taylor\My Documents\COIN-OR>cd
C:\Documents and Settings\Larry A. Taylor\My Documents\COIN-OR
C:\Documents and Settings\Larry A. Taylor\My Documents\COIN-OR>dir
Volume in drive C has no label.
Volume Serial Number is 07D1-0B0E
Directory of C:\Documents and Settings\Larry A. Taylor\My Documents\COIN-
OR
03/13/2007 12:04 PM <DIR> .
03/13/2007 12:04 PM <DIR> ..
03/08/2007 11:12 AM <DIR> Bonmin-0.1.1
03/13/2007 12:26 PM <DIR> Vol-1.0.0
03/13/2007 03:10 PM <DIR> Clp-1.3.3-win32-msvc8
03/13/2007 06:05 PM <DIR> CoinMP
03/13/2007 06:25 PM <DIR> MSVisualStudio
03/14/2007 03:19 PM 296,108 saltzman-OSI-2006.pdf
03/14/2007 04:09 PM 190,060 tkr2_symphony.pdf
03/14/2007 04:40 PM 66,037 CORS2004-OSI.pdf
03/14/2007 06:18 PM <DIR> FlopC++
03/15/2007 06:28 PM <DIR> TestCoinMP
03/15/2007 07:37 PM <DIR> TestCoinMP1
05/31/2007 02:51 PM <DIR> BINARY DOWNLOAD
06/07/2007 03:50 PM <DIR> WrapCoinMP
08/08/2007 03:06 PM 9,969 Doxyfile
08/08/2007 03:06 PM <DIR> html
08/08/2007 03:06 PM <DIR> latex
08/21/2007 12:04 PM <DIR> bin
08/21/2007 12:04 PM <DIR> doc
11/16/2007 07:08 PM <DIR> FEEDBACk
4 File(s) 562,174 bytes
17 Dir(s) 4,700,372,992 bytes free
C:\Documents and Settings\Larry A. Taylor\My Documents\COIN-OR>cd bin*
C:\Documents and Settings\Larry A. Taylor\My Documents\COIN-OR\BINARY
DOWNLOAD>d
ir
Volume in drive C has no label.
Volume Serial Number is 07D1-0B0E
Directory of C:\Documents and Settings\Larry A. Taylor\My Documents\COIN-
OR\BIN
ARY DOWNLOAD
05/31/2007 02:51 PM <DIR> .
05/31/2007 02:51 PM <DIR> ..
05/31/2007 02:53 PM <DIR> Clp-1.3.3-win32-msvc8
05/31/2007 02:56 PM <DIR> coin-win32-msvc7-13Feb06
11/16/2007 06:09 PM 3,328,485 coin-win32-msvc6-24Feb06.zip
1 File(s) 3,328,485 bytes
4 Dir(s) 4,700,372,992 bytes free
C:\Documents and Settings\Larry A. Taylor\My Documents\COIN-OR\BINARY
DOWNLOAD>c
d clp*
C:\Documents and Settings\Larry A. Taylor\My Documents\COIN-OR\BINARY
DOWNLOAD\C
lp-1.3.3-win32-msvc8>dir
Volume in drive C has no label.
Volume Serial Number is 07D1-0B0E
Directory of C:\Documents and Settings\Larry A. Taylor\My Documents\COIN-
OR\BIN
ARY DOWNLOAD\Clp-1.3.3-win32-msvc8
05/31/2007 02:53 PM <DIR> .
05/31/2007 02:53 PM <DIR> ..
11/08/2006 03:07 PM 16 AUTHORS
05/31/2007 02:53 PM <DIR> bin
05/31/2007 02:53 PM <DIR> include
05/31/2007 02:53 PM <DIR> lib
11/08/2006 03:07 PM 11,611 LICENSE
11/08/2006 03:07 PM 1,837 README
3 File(s) 13,464 bytes
5 Dir(s) 4,700,372,992 bytes free
C:\Documents and Settings\Larry A. Taylor\My Documents\COIN-OR\BINARY
DOWNLOAD\C
lp-1.3.3-win32-msvc8>cd bin
C:\Documents and Settings\Larry A. Taylor\My Documents\COIN-OR\BINARY
DOWNLOAD\C
lp-1.3.3-win32-msvc8\bin>dir
Volume in drive C has no label.
Volume Serial Number is 07D1-0B0E
Directory of C:\Documents and Settings\Larry A. Taylor\My Documents\COIN-
OR\BIN
ARY DOWNLOAD\Clp-1.3.3-win32-msvc8\bin
05/31/2007 02:53 PM <DIR> .
05/31/2007 02:53 PM <DIR> ..
11/08/2006 03:46 PM 1,155,072 clp.exe
1 File(s) 1,155,072 bytes
2 Dir(s) 4,700,372,992 bytes free
C:\Documents and Settings\Larry A. Taylor\My Documents\COIN-OR\BINARY
DOWNLOAD\C
lp-1.3.3-win32-msvc8\bin>clp.exe
Coin LP version 1.03.03, build Nov 8 2006
Clp takes input from arguments ( - switches to stdin)
Enter ? for list of commands or help
Clp:directory c://temp//
Clp:import ch108-prob1.mps
... SKIPPED ...
Clp:primals
... SKIPPED ...
Presolved problem not optimal, resolve after postsolve
After Postsolve, objective 2.71674e-005, infeasibilities - dual 0.00104051
(333)
, primal 3903.52 (6)
0 Obj 2.71674e-005 Primal inf 0.0464045 (4) Dual inf 4.06771e+010 (9)
7 Obj 4.87297 Primal inf 3.78856e-007 (1) Dual inf 0.000600785 (58)
7 Obj 4.87297 Primal inf 3.78856e-007 (1)
Optimal - objective value 3793.44
Optimal objective 3793.436084 - 184 iterations time 0.282, Presolve 0.06
Clp:
}}}
Notice that this was the clp.exe of the binary download clp-1.3.3-win32-
msvc8.
Even for this earlier version, it does not get the correct answer if you
type 'duals'.
What is even weirder is that if you do the same problem in clp.exe twice
in a row (e.g., duals followed by duals, or other combinations), I get
different answers. Something is not clearing out between optimizations.
Also, although when it gets the right answer, 4.87, it is not reported
correctly in the same line as the "optimal" report.
LAT
--
Ticket URL: <https://projects.coin-or.org/Clp/ticket/15>
COIN-OR Linear Programming Solver <http://projects.coin-or.org/Clp>
A linear programming solver.
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