Re: [ojAlgo-user] LinearSolver problem

[Anders P. <an...@op...>]

No, you don't do anything wrong. The simplex solver has problems with some (redundant) problem formulations. I haven't figured out how to solve it yet. In this case you don't really have an optimisation problem. (You don't even give values for "c".) All you need to do is solve

Ax= B

where A=
  1 -2  0
  0  1  1
  1  0  0
and B=
   0
 100
  10



The validateSolution() method should of course also check the variable boundaries. This will be fixed soon.


/Anders


On 17 nov 2009, at 16.33, Pierre AUSLAENDER wrote:

> 
> Hi Anders, 
> 
> I have a very simple linear test with only 2 variables and 1 constraint that fails. Here is the test case. 
> 
> We have variables x0 and x1, with values between 0 and 100, and we only require x0 = 2*x1. 
> 
> 
> 
> "test1" sets x0 = 10 and returns INFEASIBLE 
> "test2" sets x1 = 5 and returns OPTIMAL 
> 
> Both tests have strictly one and the same solution though. 
> 
> Did I do something wrong? 
> 
> I have a second question: ExpressionsBasedModel.validateSolution(...) does not check the variable boundaries. They only check the expressions added via "add...Expression(...)". Is this on purpose? 
> 
> Thanks, 
> Pierre
> 
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