Originally posted by: SystemAdmin

[daniel said:]

hello,

I use to work with version 3.7 of OPL. I'm finally migrating to the latest version. I encountered a problem while trying to write a constraint.

In version 3.7 I use to write something like:

forall(i in Areas)
  Volume[i]*Harvest[i] = sum( <i,j> in Connections: c.i =i) HauledVolume[c];

I could specify in the summation "such as c.i=i". By doing this, I do a summation on j.

In version 6.x I wrote:

forall(i in Areas)
  Volume[i]*Harvest[i] == sum( <i,j> in Connections: c.i ==i) HauledVolume[c];

the "c" in "c.i" is always underlined in red. I don't know why. What am I doing wrong? Is it because we cannot use the "such as..." in a constraint?
#DecisionOptimization
#MathematicalProgramming-General

Originally posted by: SystemAdmin

[alain.chabrier said:]

Hi,

I think you can do :


forall(i in Areas)
  Volume*Harvest == sum( <i,j> in Connections) HauledVolume[<i,j>];

slicing on i is implicit.

or

forall(i in Areas)
  Volume*Harvest == sum( c in Connections: c.i ==i) HauledVolume[c];

slicing in implicit

hope this helps,

Alain
#DecisionOptimization
#MathematicalProgramming-General

Originally posted by: SystemAdmin

[daniel said:]

the first code seems to work. The second does not.

Thank you for your help.

Daniel
#DecisionOptimization
#MathematicalProgramming-General