help-glpk
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Help-glpk] min() & max() functions alternatives to use non numeric


From: Andrew Makhorin
Subject: Re: [Help-glpk] min() & max() functions alternatives to use non numeric parameters
Date: Thu, 28 Apr 2011 19:59:33 +0400

> Andrew, you suggest that  z= -max(x, y)  (negative of max) can
> be modeled  through min, not z=max(x,y), is that right?
> 

Minimizing an objective like 

   z = +max(x1,x2,...)+max(x3,x4,x5,...)+max(...)+ ...

does not need binaries, because the objective is convex. Obviously, if
the objective is the following:

   z = +max(x1,x2,...)-min(x3,x4,x5,...)+...

we can substitute -min(x3,x4,x5,...) = +max(-x3,-x4,-x5,...).
Maximization case can be derived by multiplying the latter by -1:

   maximize z = -max(x1,x2,...)+min(x3,x4,x5,...)+...

that gives exactly the same objective as in nikel's question (note that
max's have a minus sign while min's have a plus sign).




reply via email to

[Prev in Thread] Current Thread [Next in Thread]