Your semantics are incorrect.

 

Irrational means the number can not be represented as P/Q, where P and Q
are integers.

 

For example, 1/3 is not irrational.  It is a rational number that is
repeating in the base 10 numbering system.

 

The sqrt(2) is irrational.

 

Note that your proposed fix - to represent the objective value using
only integer coefficients - is not a fix in general since the course of
the linear/integer program will probably have many non-integer values in
the tableau.

 

More importantly, note that your problem has multiple optimal.  x_1 = 0,
x_2 = 6 is feasible with objective value of 1.

 

Your proposed solution of x_1=2, x_2=2 is feasible, with the same
objective value of 1.

 

________________________________

From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On
Behalf Of Vijay Patil
Sent: Monday, August 11, 2008 2:02 PM
To: [email protected]
Subject: [Help-glpk] Irrational numbers

 

In one of application using GLPK, I am facing a problem because of not
being able to represent irrational numbers/values correctly (as obj.
func. coeff.).
Actually these values are dual values and are obtained from glpk itself.
Since they are approximated there is a problem (loss of information).

If you have some experience/expertize dealing with irrational numbers or
knowledge of floating point representation, you might be interested in 
having a look at the problem. 

http://code.google.com/p/cspsol/issues/detail?id=1#c2

Any workarounds to deal with this problem?

Thanks
-- 
Vijay Patil

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