Ranges

Declaring ranges

To specify an integer range, you give its lower and upper bounds, as in

range Rows = 1..10;

which declares the range value 1..10. The lower and upper bounds can also be given by expressions, as in

int n = 8;
range Rows = n+1..2*n+1;

Once a range has been defined, you can use it as an array indexer.

Whenever a range is empty, i.e. its upper bound is less than its lower bound, it is automatically normalized to 0..-1 (in other words, all empty ranges are equal).

The range declaration

An integer range is typically used:

• as an array index in an array initialization expression

  
  range R = 1..100;
  int A[R]; // A is an array of 100 integers
  

• as an iteration range

  
  range R = 1..100;
  forall(i in R) {
     //element of a loop
     ...
  }
  

• as the domain of an integer decision variable

  
  dvar int i in R;
  

The range float declaration

A range float data type consists of a couple of float values specifying an interval. It is typically used as the domain of a floating-point decision variable.

range float X = 1.0..100.0;
dvar float x in X;