fmk - adding assignments for day 4

assignments/C-Day4/ex1/gather1.c

@@ -0,0 +1,40 @@
+#include <mpi.h>
+#include <stdio.h>
+#include <stdlib.h>
+#define LUMP 5
+
+int main(int argc, char **argv) {
+
+  int numP, procID;
+
+  // the usual mpi initialization
+  MPI_Init(&argc, &argv);
+  MPI_Comm_size(MPI_COMM_WORLD, &numP);
+  MPI_Comm_rank(MPI_COMM_WORLD, &procID);
+
+  int *globalData=NULL;
+  int localData[LUMP];
+
+  // process 0 is only 1 that needs global data
+  if (procID == 0) {
+    globalData = malloc(LUMP * numP * sizeof(int) );
+    for (int i=0; i<LUMP*numP; i++)
+      globalData[i] = 0;
+  }
+
+  for (int i=0; i<LUMP; i++)
+    localData[i] = procID*10+i;
+
+  MPI_Gather(localData, LUMP, MPI_INT, globalData, LUMP, MPI_INT, 0, MPI_COMM_WORLD);
+
+  if (procID == 0) {
+    for (int i=0; i<numP*LUMP; i++)
+      printf("%d ", globalData[i]);
+    printf("\n");
+  }
+
+  if (procID == 0)
+    free(globalData);
+
+  MPI_Finalize();
+}

assignments/C-Day4/ex1/pi.c

@@ -0,0 +1,23 @@
+#include <stdio.h>
+#include <time.h>
+#include <math.h>
+
+static long int numSteps = 1000000000;
+
+int main() {
+
+  // perform calculation
+  double pi   = 0;
+  double dx = 1./numSteps;
+  double x  = dx*0.50;
+
+  for (int i=0; i<numSteps; i++) {
+    pi += 4./(1.+x*x);
+    x += dx;
+  }
+
+  pi *= dx;
+
+  printf("PI = %16.14f Difference from math.h definition %16.14f \n",pi, pi-M_PI);
+  return 0;
+}

assignments/C-Day4/ex1/solution/mpiPI.c

@@ -0,0 +1,54 @@
+#include <mpi.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+#define LUMP 1
+
+static long int numSteps = 1000000000;
+
+int main(int argc, char **argv) {
+
+  int numP, procID;
+
+  // the usual mpi initialization
+  MPI_Init(&argc, &argv);
+  MPI_Comm_size(MPI_COMM_WORLD, &numP);
+  MPI_Comm_rank(MPI_COMM_WORLD, &procID);
+
+ double *globalData=NULL;
+ double localData[LUMP];
+
+  // process 0 is only 1 that needs global data
+  if (procID == 0) {
+    globalData = (double *)malloc(LUMP * numP * sizeof(double) );
+    for (int i=0; i<LUMP*numP; i++)
+      globalData[i] = 0;
+  }
+  double myPart = 0;
+  double dx = 1./numSteps;
+  double x  = dx*0.50;
+
+  for (int i=procID; i<numSteps; i+=numP) {
+    x = (i+.5)*dx;
+    myPart += 4./(1.+x*x);
+  }
+
+  myPart *= dx;
+
+  //  localData[0] = myPart;
+
+  MPI_Gather(&myPart, LUMP, MPI_DOUBLE, globalData, LUMP, MPI_DOUBLE, 0, MPI_COMM_WORLD);
+
+  double pi = 0;
+  if (procID == 0) {
+    for (int i=0; i<numP; i++)
+      pi += globalData[i];
+    printf("PI = %16.14f Difference from math.h definition %16.14f \n",pi, pi-M_PI);
+  }
+
+
+  if (procID == 0)
+    free(globalData);
+
+  MPI_Finalize();
+}

assignments/C-Day4/ex1/submit.sh

@@ -0,0 +1,19 @@
+#!/bin/bash
+#--------------------------------------------------------------------
+# Generic SLURM script – MPI Hello World
+#
+# This script requests 1 node and 8 cores/node (out of total 64 avail)
+# for a total of 1*8 = 8 MPI tasks.
+#---------------------------------------------------------------------
+#SBATCH -J myjob
+#SBATCH -o myjob.%j.out 
+#SBATCH -e myjob.%j.err 
+#SBATCH -p development
+#SBATCH -N 1
+#SBATCH -n 8
+#SBATCH -t 00:02:00
+#SBATCH -A DesignSafe-SimCenter
+
+ibrun ./pi 
+
+

assignments/C-Day4/ex1/submitPI.sh

@@ -0,0 +1,19 @@
+#!/bin/bash
+#--------------------------------------------------------------------
+# Generic SLURM script – MPI Hello World
+#
+# This script requests 1 node and 8 cores/node (out of total 64 avail)
+# for a total of 1*8 = 8 MPI tasks.
+#---------------------------------------------------------------------
+#SBATCH -J myjob
+#SBATCH -o myjob.%j.out 
+#SBATCH -e myjob.%j.err 
+#SBATCH -p development
+#SBATCH -N 1
+#SBATCH -n 1
+#SBATCH -t 00:02:00
+#SBATCH -A DesignSafe-SimCenter
+
+ibrun ./pi 
+
+

assignments/C-Day4/ex2/scatterArray.c

@@ -0,0 +1,65 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <mpi.h>
+
+int main(int argc, char** argv) {
+
+    int procID, numP;
+
+    double* globalVector = NULL;
+    double* localVector = NULL;
+
+    MPI_Init(&argc, &argv);
+    MPI_Comm_rank(MPI_COMM_WORLD, &procID);
+    MPI_Comm_size(MPI_COMM_WORLD, &numP);
+
+    if (argc != 2) {
+      printf("Error correct usage: app vectorSize\n");
+      return 0;
+    }
+    int vectorSize = atoi(argv[1]);
+    int remainder = vectorSize % numP;
+
+    // Only the root process initializes the global array
+    if (procID == 0) {
+      globalVector = (double*)malloc(sizeof(double) * vectorSize);
+      srand(50);
+      for (int i = 0; i < vectorSize; i++) {
+	double random_number = 1.0 + (double)rand() / RAND_MAX;
+	globalVector[i] = random_number;
+      }
+    }
+
+    // Determine the size of the local array for each process
+    int localSize = vectorSize / numP;
+
+    // Allocate memory for the local array
+    localVector = (double*)malloc(sizeof(double) * localSize);
+
+    // Scatter the global array to all processes
+    MPI_Scatter(globalVector, localSize, MPI_DOUBLE,
+                localVector, localSize, MPI_DOUBLE,
+                0, MPI_COMM_WORLD);
+
+    // Print the local array for each process
+    printf("Process %d received: ", procID);
+    for (int i = 0; i < localSize; i++) {
+        printf("%.2f ", localVector[i]);
+    }
+    printf("\n");
+
+    // process0 has some stuff in the globalArray that was not sent!
+    if (procID == 0) {
+      printf("Process 0 Additional NOT SENT still in globalVector: ");    
+      for (int i=numP*localSize; i<vectorSize; i++)
+        printf("%.2f ", globalVector[i]);
+      printf("\n");
+    }
+
+    // Clean up memory
+    free(globalVector);
+    free(localVector);
+
+    MPI_Finalize();
+    return 0;
+}

docs/_sources/source/assignment_C4.rst.txt

@@ -1,6 +1,9 @@
 C: Assignments Day 4
 ====================
 
+Problem 1: Parallelize **pi.c** using **MPI**
+---------------------------------------------
+
 Today we are going to parallelize the **pi.c** code you developed for day 1. to run at TACC you will need to use either **idev** or **sbatch**.
 
 The figure below shows an method to compute **pi** by numerical integration. We would like you to implement that computation in a **C** program.
@@ -41,8 +44,6 @@ The solution `pi.c' is in the solitions/C-Day1/pi folder. The contents of that f
 
    Our solution of **pi.c** as written as a loop dependency which may need to revise for tomorrows OpenMPI problem.
 
-Problem 1: Parallelize **pi.c** using **MPI**
-------------------------------------
 
 You are to modify the **pi.c** application and run it to use mpi. I have included a few files in code/parallel/ExercisesDay4/ex1 to help you. They include **pi.c** above, gather1.c and a submit.sh script. **gather1.c** was presented in the video, and us shown below:
 
@@ -56,7 +57,22 @@ The submit script is as shown below.
   :linenos:
 
 
-Problem 2: Bonus Parallelize your **matMul** solution using **MPI**
+Problem 2: Compute the Norm of a vector using **MPI**
+-----------------------------------------------------
+
+Given what you just did with **pi** can you now write a program to compute the norm of  avector. In the **ex2** directory I have placed a file **scatterArray.c**. This file will use MPI_Scatter to send components of the vector to the different processes in the running parallel application.
+
+
+.. literalinclude:: ./assignments/c4/scatterArray.c
+  :language: c		    
+  :linenos:
+
+.. note::
+
+   The vector size may not always be divisible by the number of processes. In such a case there will be additional terms not sent. Don;t forget to include them in the computation!
+
+
+Problem 3: Bonus Parallelize your **matMul** solution using **MPI**
 -------------------------------------------------------------------
 
 If you want a more complicated problem to parallelize, I suggest parallelizing you matMul application from Day 2.

docs/index.html

@@ -279,7 +279,8 @@ <h1>Welcome to the NHERI-SimCenter 2023 Programming Bootcamp<a class="headerlink
 </li>
 <li class="toctree-l2"><a class="reference internal" href="source/assignment_C4.html">C: Assignments Day 4</a><ul>
 <li class="toctree-l3"><a class="reference internal" href="source/assignment_C4.html#problem-1-parallelize-pi-c-using-mpi">Problem 1: Parallelize <strong>pi.c</strong> using <strong>MPI</strong></a></li>
-<li class="toctree-l3"><a class="reference internal" href="source/assignment_C4.html#problem-2-bonus-parallelize-your-matmul-solution-using-mpi">Problem 2: Bonus Parallelize your <strong>matMul</strong> solution using <strong>MPI</strong></a></li>
+<li class="toctree-l3"><a class="reference internal" href="source/assignment_C4.html#problem-2-compute-the-norm-of-a-vector-using-mpi">Problem 2: Compute the Norm of a vector using <strong>MPI</strong></a></li>
+<li class="toctree-l3"><a class="reference internal" href="source/assignment_C4.html#problem-3-bonus-parallelize-your-matmul-solution-using-mpi">Problem 3: Bonus Parallelize your <strong>matMul</strong> solution using <strong>MPI</strong></a></li>
 </ul>
 </li>
 <li class="toctree-l2"><a class="reference internal" href="source/assignment_C5.html">C: Assignments Day 5</a><ul>