Re: [Help-glpk] Implementing conditional amount constraints using binary variables

[Yaron Kretchmer]

Both a and b can be bounded by a  large M.
So let me reformulate my problem:

0 <= a <= M

if a > 0 : a=b

if a=0 : 0<=b<=M

Thanks
Kretch

On Wed, Jun 3, 2009 at 8:42 AM, Michael Hennebry <address@hidden> wrote:

On Tue, 2 Jun 2009, Yaron Kretchmer wrote:

I would like to implement the following condition on two variables:
*) If the amount of variable *a* is greater than 0, then the amount of
variable *b* needs to be equal to that of a.

How much greater?
Absent a finite number, I suspect that there is no MILP representation.
If there is only one such pair of variables,
the best solution might be to represent it as two separate problems.

*) If the amount of variable a is zero, then the amount of variable b is not
restricted.

--
Michael   address@hidden
"Pessimist: The glass is half empty.
Optimist:   The glass is half full.
Engineer:   The glass is twice as big as it needs to be."