PrivateDist

Usage

use PrivateDist;

or

import PrivateDist;

Warning

PrivateDist is unstable and may change in the future

record privateDist : writeSerializable

This privateDist distribution maps each index i between 0 and numLocales-1 to Locales[i].

The index set of a domain distributed over privateDist is always 0..numLocales-1, regardless of the domain’s rank, and cannot be changed.

This module declares a module-level constant of type privateDist named PrivateSpace for use as a convenience (so that user programs do not need to declare their own).

const PrivateSpace: domain(1) dmapped new privateDist();

Example

The following code declares a Private-distributed array A. The forall loop visits each locale and sets the array element corresponding to that locale to that locale’s ID.

use PrivateDist;

var A: [PrivateSpace] int;
forall a in A do
  a = a.locale.id;
writeln(A);

When run on 6 locales, the output is:

0 1 2 3 4 5

Data-Parallel Iteration

A forall loop over a privateDist domain or array runs a single task on each locale. That task executes the loop’s iteration corresponding to that locale’s index in the Locales array.

Limitations

Domains and arrays distributed over this distribution do not provide some standard domain/array functionality.

This distribution may perform unnecessary communication between locales.