Reduce

Syntax

reduce[root,operation]

Semantics

All processes in the group will combine their values together at the root process and then the operation will be performed on them.

Example

function void main() {
   var t:Int::allocated[multiple[]];
   var x:Int::allocated[multiple[]];
   var p;
   par p from 0 to 3 {
      x:(x::reduce[1,"max"];
      x:=p;
      t:=x;
   };
};

In this example, x is to be reduced, with the root as process 1 and the operation will be to find the maximum number. In the first assignment x:=p all processes will combine their values of p and the maximum will be placed into process 1's x. In the second assignment t:=x processes will combine their values of x and the maximum will be placed into process 1's t.

Since: Version 0.41b

Supported operations

Operator	Description
max	Identify the maximum value
min	Identify the minimum value
sum	Sum all the values together
prod	Generate product of all values