[TRAC] PrimalInfeasible though everything seems fine

[qtothec]

Moved from TRAC as part of COIN fORgery: https://projects.coin-or.org/Clp/ticket/49

Hi,

Depending on the version of Clp I use, the small problem at the end of this post (that is created within a C++ code using OsiClp?) either solves or crashes saying the following:

Coin0506I Presolve 7 (-4) rows, 3 (-1) columns and 14 (-9) elements
Clp0006I 0  Obj 1.9814e+08 Primal inf 1.83574e+07 (6) Dual inf 0.554116 (1)
Clp0006I 2  Obj 1.9814e+08 Primal inf 1.92093e-08 (1)
Clp0006I 2  Obj 1.9814e+08
Clp0001I Primal infeasible - objective value 1.9814e+08
Coin0505I Presolved problem not optimal, resolve after postsolve
Coin0511I After Postsolve, objective 1.9814e+08, infeasibilities - dual 0 (0), primal 0 (0)
Clp0032I PrimalInfeasible objective 198140043.9 - 4 iterations time 0.002, Presolve 0.00

On a Linux Ubuntu machine, I use the Coin Clp official package for Ubuntu Natty and everything works fine. On Mac OS X, I use the latest version from svn and it gives me the result above.

What is strange is that if I read well both infeasibilities are zero. Yet Clp says PrimalInfeasible?. What should I do?

Thanks in advance.

mylp.lp: \Problem name:

Minimize obj: -261.85349 x0 + x3 Subject To cons0: 36000 x0 + 36000 x1 + x2 = 45222222.22222 cons1: -0.04113 x2 - x3 <= -200000000 cons2: -0.04028 x2 - x3 <= -199961545.45000 cons3: -0.03940 x2 - x3 <= -199881928.40000 cons4: -0.03940 x2 - x3 <= -199881928.40000 cons5: -0.03868 x2 - x3 <= -199784873.49200 cons6: -0.03649 x2 - x3 <= -199389037.13111 cons7: -0.03303 x2 - x3 <= -198605495.00667 cons8: -0.02635 x2 - x3 <= -196664109.03822 cons9: -0.02635 x2 - x3 <= -196664109.03822 cons10: -0.02438 x2 - x3 <= -195950834.02400 Bounds

0 <= x0 <= 215 0 <= x2 <= 407000000 x3 Free

End

[jjhforrest]

Unable to reproduce (trunk)