[Coin-discuss] inconsistant behavior.

[John J Forrest]

Vivian,

I don't understand when you say the first version is dual infeasible as x,y
>=0 and <=5 (by equations).  I tried Clp on Linux and I got 5,0 and 3,4 as
solutions which is correct.

John Forrest


                                                                                                                          
                      Vivian.DeSmedt at aisystems.be                                                                         
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                      usf.ibm.com                                  Subject:  [Coin-discuss] inconsistant behavior.        
                                                                                                                          
                                                                                                                          
                      01/24/2003 11:14 AM                                                                                 
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Dear Osi,

I continue my experiment. I don't dare modifying the code yet not being
sure what should be the correct behavior. In the mean time I just try to
report the differences I observe between the solvers.

In the following test suite and in particular in test 5 glpk is the only
one to behave correctly.

I think
 - cplex fail to tell the the first verion of the problem is dual
infeasible.
 - clp fail to tell that the first version is dual infeasible and that no
optimal solution was found
 - clp fail to find a solution for the second version of the problem.

Vivian De Smedt.


ps:

Here are a readable description of both problems:

obj: 3x + y
2x + y < 10
x + 3y < 15

which is dual infeasible?


obj: x + y
2x + y < 10
x + 3y < 15

which have optimal (3, 4)


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