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add cpi (MPI) exmample

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This commit is contained in:
Stefan Lankes 2016-01-22 04:38:33 +01:00
parent 664b8b252c
commit e6bae65d25
2 changed files with 82 additions and 2 deletions
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15
hermit/usr/tests/Makefile
View file

@ -48,7 +48,7 @@ endif
default: all
all: hello.bin hello++.bin thr_hello.bin jacobi.bin hellof.bin #RCCE_minimum
all: hello.bin hello++.bin thr_hello.bin jacobi.bin hellof.bin cpi.bin #RCCE_minimum
hello++: hello++.o
@echo [LD] $@
@ -79,7 +79,7 @@ jacobi: jacobi.o
$Qchmod a-x $@.sym
thr_hello.o: thr_hello.c
@echo [CC] $@
@echo [CC] $@
$Q$(CC_FOR_TARGET) -c $(CFLAGS_FOR_TARGET) -pthread -o $@ $<
thr_hello: thr_hello.o
@ -89,6 +89,17 @@ thr_hello: thr_hello.o
$Q$(OBJCOPY_FOR_TARGET) $(STRIP_DEBUG) $@
$Qchmod a-x $@.sym
cpi.o: cpi.c
@echo [CC] $@
$Q$(CC_FOR_TARGET) -c $(CFLAGS_FOR_TARGET) -pthread -o $@ $<
cpi: cpi.o
@echo [LD] $@
$Q$(CC_FOR_TARGET) $(LDFLAGS_FOR_TARGET) $(CFLAGS_FOR_TARGET) -o $@ $< -pthread -lmpi
$Q$(OBJCOPY_FOR_TARGET) $(KEEP_DEBUG) $@ $@.sym
$Q$(OBJCOPY_FOR_TARGET) $(STRIP_DEBUG) $@
$Qchmod a-x $@.sym
RCCE_minimum: RCCE_minimum.o
@echo [LD] $@
$Q$(CC_FOR_TARGET) $(LDFLAGS_FOR_TARGET) $(CFLAGS_FOR_TARGET) -o $@ $< -lircce

69
hermit/usr/tests/cpi.c Normal file
View file

@ -0,0 +1,69 @@
/* -*- Mode: C; c-basic-offset:4 ; indent-tabs-mode:nil ; -*- */
/*
* (C) 2001 by Argonne National Laboratory.
* See COPYRIGHT in top-level directory.
*/
/*
* We take this example form the orginoal MPICH distributions
* => see COPYRIGHT statement in hermit/usr/mpich-3.2
*/
#include "mpi.h"
#include <stdio.h>
#include <math.h>
double f(double);
double f(double a)
{
return (4.0 / (1.0 + a*a));
}
int main(int argc,char *argv[])
{
int n, myid, numprocs, i;
double PI25DT = 3.141592653589793238462643;
double mypi, pi, h, sum, x;
double startwtime = 0.0, endwtime;
int namelen;
char processor_name[MPI_MAX_PROCESSOR_NAME];
MPI_Init(&argc,&argv);
MPI_Comm_size(MPI_COMM_WORLD,&numprocs);
MPI_Comm_rank(MPI_COMM_WORLD,&myid);
MPI_Get_processor_name(processor_name,&namelen);
fprintf(stdout,"Process %d of %d is on %s\n",
myid, numprocs, processor_name);
fflush(stdout);
n = 10000; /* default # of rectangles */
if (myid == 0)
startwtime = MPI_Wtime();
MPI_Bcast(&n, 1, MPI_INT, 0, MPI_COMM_WORLD);
h = 1.0 / (double) n;
sum = 0.0;
/* A slightly better approach starts from large i and works back */
for (i = myid + 1; i <= n; i += numprocs)
{
x = h * ((double)i - 0.5);
sum += f(x);
}
mypi = h * sum;
MPI_Reduce(&mypi, &pi, 1, MPI_DOUBLE, MPI_SUM, 0, MPI_COMM_WORLD);
if (myid == 0) {
endwtime = MPI_Wtime();
printf("pi is approximately %.16f, Error is %.16f\n",
pi, fabs(pi - PI25DT));
printf("wall clock time = %f\n", endwtime-startwtime);
fflush(stdout);
}
MPI_Finalize();
return 0;
}