comm.c File Reference

Broadcast an array of dtype numbers. More...

#include "superlu_ddefs.h"

Include dependency graph for comm.c:

Functions
void	bcast_tree (void *buf, int count, MPI_Datatype dtype, int root, int tag, gridinfo_t *grid, int scope, int *recvcnt)

Detailed Description

Broadcast an array of dtype numbers.

Copyright (c) 2003, The Regents of the University of California, through Lawrence Berkeley National Laboratory (subject to receipt of any required approvals from U.S. Dept. of Energy)

All rights reserved.

The source code is distributed under BSD license, see the file License.txt at the top-level directory.

-- Distributed SuperLU routine (version 1.0) --
Lawrence Berkeley National Lab, Univ. of California Berkeley.
September 1, 1999

Function Documentation

bcast_tree()

void bcast_tree	(	void *	buf,
		int	count,
		MPI_Datatype	dtype,
		int	root,
		int	tag,
		gridinfo_t *	grid,
		int	scope,
		int *	recvcnt
	)

Purpose
=======
  Broadcast an array of *dtype* numbers. The communication pattern
  is a tree with number of branches equal to NBRANCHES.
  The process ranks are between 0 and Np-1.

  The following two pairs of graphs give different ways of viewing the same
  algorithm.  The first pair shows the trees as they should be visualized
  when examining the algorithm.  The second pair are isomorphic graphs of
  of the first, which show the actual pattern of data movement.
  Note that a tree broadcast with NBRANCHES = 2 is isomorphic with a
  hypercube broadcast (however, it does not require the nodes be a
  power of two to work).

   TREE BROADCAST, NBRANCHES = 2     *    TREE BROADCAST, NBRANCHES = 3

    root=2
i=4   &______________                *
      |              \               *       root=2
i=2   &______         &______        * i=3     &______________________
      |      \        |      \       *         |          \           \
i=1   &__     &__     &__     &__    * i=1     &______     &______     &__
      |  \    |  \    |  \    |  \   *         |  \   \    |  \   \    |  \
      2   3   4   5   6   7   0   1  *         2   3   4   5   6   7   0   1


         ISOMORPHIC GRAPHS OF ABOVE, SHOWN IN MORE FAMILIAR TERMS:

               2                                           2
      _________|_________                       ___________|____________
     /         |         \                     /           |      |     \
    6          4          3                   5            0      3      4
   / \         |                             / \           |
  0   7        5                            6   7          1
  |
  1


Arguments
=========

scope