Originally posted by: sandeepsinghchauhan

availablity is data

dvar float+ S[Routes];

forall(Ro in Routes:  S[Ro]  >=  availablity[Ro]){
 
 Coupne[Ro] == multiplication and addition;

}

ERROR::
Decision variable (or expression) "S" not allowed. 

How can i resolve it and use S as a condition?

Please help

Hi,

indeed you cannot use slicing over a decision variable, what you should do instead is use a logical constraint:

dvar float+ S[Routes];

forall(Ro in Routes){
 
 (S[Ro]  >=  availablity[Ro])  => (Coupne[Ro] == multiplication and addition);

}

regards

Originally posted by: sandeepsinghchauhan

Is there any other way rather than '=> '

because in standard opl examples no where => used for conditions

please help

Hi,

you should have a look at

IDE and OPL > Optimization Programming Language (OPL) > Language User's Manual > The application areas > Tutorial: Using CPLEX logical constraints

in documentation.

If you do not like

(a)=>(b)

you may also write

(!a) || (b)

but more difficult to read for human users.

regards

Originally posted by: sandeepsinghchauhan

Thanks for your valuable reply

any example with => or || in opl examples?

Hi,

a small example:

dvar int x[1..2];

subject to
{
forall(i in 1..2) (x[i]>=1) => (x[i]==1);
forall(i in 1..2) (x[i]<=-0) => (x[i]==0);
x[1]!=x[2];
}

You may also have a look at the steelmill example where you can see the use of "or"

regards

https://www.linkedin.com/pulse/optimization-aka-prescriptive-analytics-should-we-write-fleischer

Originally posted by: sandeepsinghchauhan

Thanks