[Lemon-user] NetworkSimplex SuppyType

[Kovács Péter]

Hi Peter,

In short, if the sum of supply values is zero, then the GEQ and LEQ 
forms are actually equivalent to the equality form. That is why EQ 
option was omitted.

Consider this page of the documentation:
http://lemon.cs.elte.hu/pub/doc/1.2.1/a00005.html

Note that the sum of the expressions on the left-hand side of the 
inequalities is always zero. Therefore, the "equality" form can only be 
feasible if the sum of supply values (the right-hand side) is also zero. 
You should check this constraint before using NetworkSimplex!

However, if this precondition holds, then you can safely use 
NetworkSimplex with either GEQ or LEQ supply constraint type. If all 
inequalities hold and the sum of the left-hand side and right-hand side 
expressions are the same, then <= must be = actually for all 
constraints. That is why LEQ and EQ are equal in this case.

Regards,
Peter


On 2011.08.02. 15:42, Peter A. Kolski wrote:
 > Dear LEMON users!
 >
 > I have a supposedly simple question where I didn't find an answer to.
 >
 > In the NetworkSimplex Class, I want to set the SupplyType constrains 
for the nodes to "EQUAL".
 > Obviously supported is GEQ and LEQ. And in the API it says:
 >
 > 	"The equality form is a special case of both supply types."
 >
 > But how do I set it up in the syntax?
 >
 > Calling the parameters GEQ&&  LEO for .supplyType is invalid.
 > Calling supplyType() successively sets it to the last parameter.
 >
 > So what should I do?
 >
 >
 > Thank you very much!
 >
 >
 > Best regards
 >
 > Peter A. Kolski
 >