Allreduce

Syntax

allreduce[operation]

Semantics

Similar to the reduce type, but the reduction will be performed on each process and the result is also available to all.

Example

var x:Int::allocated[multiple[]];
var p;
par p from 0 to 3
{
   (x::allreduce["min"]):=p;
};

In this case all processes will perform the reduction on p and all processes will have the minimum value of p placed into their copy of x.

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

Since: Version 0.41b