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Identifier Expressions

Use an identifier-expression to refer to a variable, objective, constraint, or parameter location in expressions or initializations. This is the syntax for identifier-expressions :

name [ [ expression-1 [, ...expression-n] ] ] [ . suffix ]

To refer to a location in an array, follow the array name with a list of scalar expressions in square brackets ([ ]). The expression values are compared to the index set that was used to declare name. If there is more than one expression, then the values are formed into a tuple. The expression values for a valid array location must match a member of the array's index set. For example, the following code defines a parameter array A that has two valid indices that match the tuples <1,2> and <3,4>:

  
    proc optmodel; 
       set<number, number> ISET = {<1,2>, <3,4>}; 
       number A{ISET}; 
       a[1,2] = 0;  /* OK */ 
       a[3,2] = 0;  /* invalid index */
 

The first assignment is valid with this definition of the index set, but the second fails because <3,2> is not a member of the set parameter ISET.

Specify a suffix to refer to auxiliary locations for variables or objectives. See the section "Suffixes" for more information.