MPIMax.c File Reference

Functions to compute the maximum over all MPI ranks. More...

#include <mpivars.h>

Go to the source code of this file.

Functions
int	MPIMax_integer (int *global, int *var, int size, void *comm)
int	MPIMax_double (double *global, double *var, int size, void *comm)

Detailed Description

Functions to compute the maximum over all MPI ranks.

Author

Debojyoti Ghosh

Definition in file MPIMax.c.

Function Documentation

MPIMax_integer()

int MPIMax_integer	(	int *	global,
		int *	var,
		int	size,
		void *	comm
	)

Compute the global maximum over all MPI ranks in a given communicator for int datatype.

• If var is an array of size greater than 1, global will be an array of the same size with each element as the maximum value of that element in var on all the MPI ranks in the given communicator.

Parameters

global	array to contain the global maximums
var	the local array
size	size of the local array
comm	MPI communicator

Definition at line 15 of file MPIMax.c.

{
#ifdef serial
  int i;
  for (i = 0; i < size; i++)  global[i] = var[i];
#else
  MPI_Allreduce((var==global?MPI_IN_PLACE:var),global,size,MPI_INT,MPI_MAX,*((MPI_Comm*)comm));
#endif
  return(0);
}

MPIMax_double()

int MPIMax_double	(	double *	global,
		double *	var,
		int	size,
		void *	comm
	)

Compute the global maximum over all MPI ranks in a given communicator for double datatype.

• If var is an array of size greater than 1, global will be an array of the same size with each element as the maximum value of that element in var on all the MPI ranks in the given communicator.

Parameters

global	array to contain the global maximums
var	the local array
size	size of the local array
comm	MPI communicator

Definition at line 38 of file MPIMax.c.

{
#ifdef serial
  int i;
  for (i = 0; i < size; i++)  global[i] = var[i];
#else
  MPI_Allreduce((var==global?MPI_IN_PLACE:var),global,size,MPI_DOUBLE,MPI_MAX,*((MPI_Comm*)comm));
#endif
  return(0);
}