From 50bf605b19ba030a9c39a41ecf6021f2ae25d748 Mon Sep 17 00:00:00 2001
From: Erik Strand <erik.strand@cba.mit.edu>
Date: Sat, 6 Mar 2021 13:17:27 -0500
Subject: [PATCH] Add MPI pi calculation (CPU)
---
mpi_pi_cpu/.gitignore | 2 ++
mpi_pi_cpu/Makefile | 2 ++
mpi_pi_cpu/load_modules.sh | 5 ++++
mpi_pi_cpu/mpi_pi_cpu.c | 53 +++++++++++++++++++++++++++++++++++++
mpi_pi_cpu/mpi_pi_cpu.slurm | 15 +++++++++++
5 files changed, 77 insertions(+)
create mode 100644 mpi_pi_cpu/.gitignore
create mode 100644 mpi_pi_cpu/Makefile
create mode 100755 mpi_pi_cpu/load_modules.sh
create mode 100644 mpi_pi_cpu/mpi_pi_cpu.c
create mode 100644 mpi_pi_cpu/mpi_pi_cpu.slurm
diff --git a/mpi_pi_cpu/.gitignore b/mpi_pi_cpu/.gitignore
new file mode 100644
index 0000000..130dcdd
--- /dev/null
+++ b/mpi_pi_cpu/.gitignore
@@ -0,0 +1,2 @@
+mpi_pi_cpu
+output
diff --git a/mpi_pi_cpu/Makefile b/mpi_pi_cpu/Makefile
new file mode 100644
index 0000000..928fa28
--- /dev/null
+++ b/mpi_pi_cpu/Makefile
@@ -0,0 +1,2 @@
+mpi_pi_cpu: mpi_pi_cpu.c
+ mpicc $< -o $@
diff --git a/mpi_pi_cpu/load_modules.sh b/mpi_pi_cpu/load_modules.sh
new file mode 100755
index 0000000..8190933
--- /dev/null
+++ b/mpi_pi_cpu/load_modules.sh
@@ -0,0 +1,5 @@
+#!/bin/bash
+
+module purge
+module load spack git gcc/7.3.0 openmpi/3.1.4-pmi-cuda-ucx
+
diff --git a/mpi_pi_cpu/mpi_pi_cpu.c b/mpi_pi_cpu/mpi_pi_cpu.c
new file mode 100644
index 0000000..dae3498
--- /dev/null
+++ b/mpi_pi_cpu/mpi_pi_cpu.c
@@ -0,0 +1,53 @@
+/*
+* mpipi.c
+* Neil Gershenfeld 2/5/11
+* Erik Strand 3/6/2021
+* use MPI to evaluate pi by summation
+*/
+
+#include <stdio.h>
+#include <mpi.h>
+#include <sys/time.h>
+
+// number of terms evaluated by each process
+#define NPTS 100000
+
+void main(int argc, char** argv) {
+ // variables used by all ranks
+ int rank, i, istart, iend;
+ double sum, pi;
+
+ // variables used only by rank 0
+ unsigned long int start_time, end_time;
+ struct timeval start, end;
+ int nproc;
+ double mflops;
+
+ MPI_Init(&argc, &argv);
+ MPI_Comm_rank(MPI_COMM_WORLD, &rank);
+
+ if (rank == 0) {
+ MPI_Comm_size(MPI_COMM_WORLD, &nproc);
+ gettimeofday(&start, NULL);
+ }
+
+ istart = NPTS * rank;
+ iend = NPTS * (rank + 1);
+ sum = 0.0;
+ for (i = istart; i <= iend; ++i) {
+ sum += 0.5 / ((i - 0.75) * (i - 0.25));
+ }
+ MPI_Reduce(&sum, &pi, 1, MPI_DOUBLE, MPI_SUM, 0, MPI_COMM_WORLD);
+
+ if (rank == 0) {
+ gettimeofday(&end, NULL);
+ start_time = start.tv_sec * 1e6 + start.tv_usec;
+ end_time = end.tv_sec * 1e6 + end.tv_usec;
+ mflops = (double)nproc * NPTS * 5.0 / (end_time - start_time);
+ printf("processes = %d, terms per process = %ld, total terms = %ld\n", nproc, NPTS, nproc * NPTS);
+ printf("time = %f, estimated MFlops = %f\n", (end_time - start_time) / 1.0e6, mflops);
+ printf("pi ~ %f\n", pi);
+ }
+
+ MPI_Finalize();
+}
diff --git a/mpi_pi_cpu/mpi_pi_cpu.slurm b/mpi_pi_cpu/mpi_pi_cpu.slurm
new file mode 100644
index 0000000..f224a2e
--- /dev/null
+++ b/mpi_pi_cpu/mpi_pi_cpu.slurm
@@ -0,0 +1,15 @@
+#!/bin/bash
+#SBATCH -J mpi_pi_cpu
+#SBATCH -o output/mpi_pi_cpu_%j.out
+#SBATCH -e output/mpi_pi_cpu_%j.err
+#SBATCH --nodes=2
+#SBATCH --ntasks-per-node=8
+#SBATCH --gres=gpu:0
+#SBATCH --cpus-per-task=1
+#SBATCH --ntasks-per-core=1
+#SBATCH --threads-per-core=1
+#SBATCH --mem=1G
+#SBATCH --time 00:05:00
+
+source ./load_modules.sh
+srun ./mpi_pi_cpu
--
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