Create mergesort.cpp

mergesort.cpp

@@ -0,0 +1,150 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <iostream>
+#include <time.h>
+#include <mpi.h>
+using namespace std;
+
+void merge(int *a, int *b, int l, int m, int r);
+//main function for mearge
+void mergeSort(int *a, int *b, int l, int r);
+int main(int argc, char** argv)
+{
+
+int ArraySize=6;
+int *original_array = new int[ArraySize] ;
+cout<<"\n\n Done by Maitreyee Paliwal \n\n";
+
+
+int Process_rank;
+int ProcessSize;
+MPI_Init(&argc, &argv);
+MPI_Comm_rank(MPI_COMM_WORLD, &Process_rank);
+MPI_Comm_size(MPI_COMM_WORLD, &ProcessSize);
+//Print array
+if (Process_rank==0)
+{
+cout << " Array to sort\n ";
+for (int c = 0; c <ArraySize; c++)
+{
+original_array[c] = rand() % ArraySize;
+if(c==ArraySize-1){
+cout << original_array[c];
+}
+else{
+cout << original_array[c]<<", ";}
+}
+cout << "\n";
+}
+
+int SizeForSub = ArraySize / ProcessSize;
+
+int *sub_array = new int[SizeForSub];
+MPI_Scatter(original_array, SizeForSub, MPI_INT, sub_array, SizeForSub, MPI_INT, 0, MPI_COMM_WORLD);
+
+for (int i = 0; i < ProcessSize; i++)
+{
+cout << "sub array (Sub Parallel Process): " << Process_rank << "\n";
+for (int c = 0; c < SizeForSub; c++)
+{
+if(c==SizeForSub-1){
+cout << sub_array[c];
+}
+else{
+cout << sub_array[c]<<", ";
+}
+}
+printf("\n");
+break;
+}
+int *tmp_array = new int[SizeForSub];
+mergeSort(sub_array, tmp_array, 0, (SizeForSub - 1));
+
+int *sorted =NULL;
+if(Process_rank== 0)
+{
+sorted = new int[ArraySize];
+}
+MPI_Gather(sub_array, SizeForSub, MPI_INT, sorted, SizeForSub, MPI_INT, 0,
+MPI_COMM_WORLD);
+
+if(Process_rank == 0)
+{
+int *other_array =new int[ArraySize] ;
+mergeSort(sorted, other_array, 0, (ArraySize - 1));
+
+cout<<"The sorted array is:\n";
+for(int c = 0; c <ArraySize; c++)
+{
+if(c==ArraySize-1){
+cout << sorted[c];
+}
+else{
+cout << sorted[c]<<", ";
+}
+}
+cout<<"\n\n\n";
+free(sorted);
+free(other_array);
+}
+free(original_array);
+free(sub_array);
+free(tmp_array);
+
+MPI_Barrier(MPI_COMM_WORLD);
+MPI_Finalize();
+}
+
+
+void merge(int *a, int *b, int l, int m, int r)
+{
+int h, i, j, k;
+h = l;
+i = l;
+j = m + 1;
+while ((h <= m) && (j <= r))
+{
+if (a[h] <= a[j])
+{
+b[i] = a[h];
+h++;
+}
+else
+{
+b[i] = a[j];
+j++;
+}
+i++;
+}
+if (m < h)
+{
+for (k = j; k <= r; k++)
+{
+b[i] = a[k];
+i++;
+}
+}
+else
+{
+for (k = h; k <= m; k++)
+{
+b[i] = a[k];
+i++;
+}
+}
+for (k = l; k <= r; k++)
+{
+a[k] = b[k];
+}
+}
+
+void mergeSort(int *a, int *b, int l, int r)
+{
+int m;
+if (l < r) {
+m = (l + r) / 2;
+mergeSort(a, b, l, m);
+mergeSort(a, b, (m + 1), r);
+merge(a, b, l, m, r);
+}
+}