works on one processor

untitled/main.cpp

@@ -0,0 +1,140 @@
+#include <iostream>
+#include <random>
+#include <mpi.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <ctime>
+#define MCW MPI_COMM_WORLD
+using namespace std;
+int main(int argc, char **argv){ int rank, size;
+  int N = 6;
+  MPI_Init(&argc, &argv); MPI_Comm_rank(MCW, &rank);
+  MPI_Comm_size(MCW, &size);
+
+  int* C=(int*)malloc(sizeof(int) *(N/size));
+  bool finished;
+
+
+  //random number generator
+  std::random_device dev;
+  std::mt19937 rng(dev());
+  std::uniform_int_distribution<std::mt19937::result_type> dist5(1,5); // distribution in range [1, 6]
+
+  //initialize array
+  int **world = nullptr, *worldData = nullptr;
+  if(rank == 0){
+    worldData = (int *)malloc(sizeof(int)*N*N);
+    world = (int **)malloc(sizeof(int*) * N);
+    for(int i = 0; i < N; i++) {
+      world[i] = &(worldData[i*N]);
+    }
+
+    //Sets up world
+    for(int i = 0; i < N; i++){
+      for( int j =0; j < N; j++){
+        if(dist5(rng) == 1){
+          world[i][j] = 1;
+        }else{
+          world[i][j] = 0;
+        }
+        cout << world[i][j] << " ";
+      }
+      cout << endl;
+    }
+    cout << endl << endl;
+    finished = false;
+  }
+  MPI_Barrier(MCW);
+
+
+
+  do{
+    MPI_Bcast (world, N*N, MPI_INT, 0, MCW);
+
+    int from = rank * N/size;
+    int to = ((rank+1) * N/size);
+
+    //Do Computations.
+    for(int i = 0; i < N; i++){
+      // Scatter the random numbers to all processes
+      cout << "ABOVE SCATTER" << endl;
+      MPI_Scatter (rank == 0 ? &(world[0][0]) : NULL, to-from, MPI_INT, C, to-from, MPI_INT, 0, MCW);
+      cout << "Rank: " << rank << endl;
+      for(int i = 0; i < N/size; i++){
+        cout << C[i] << " ";
+      }cout << endl;
+
+
+      for(int j = from, k = 0; j < to; j++, k++){
+        cout << "MADE IT BACK TO THE TOP!!!!!!!!!!!!!!" << endl;
+        cout << "K: " << k << endl << endl;
+//        cout << "From " << from<<" TO: " << to  <<" process: " << rank <<" j: " << j << " i: " << i<< endl;
+        int neighbors = 0;
+        //Above 3 cells
+        if(i - 1 >= 0) {
+          if (world[i - 1][j] == 1)
+            neighbors++;
+          if (j - 1 >= 0)
+            if (world[i - 1][j - 1] == 1)
+              neighbors++;
+          if (j + 1 < N)
+            if (world[i - 1][j + 1] == 1)
+              neighbors++;
+        }
+        //Below 3 Cells
+        if(i + 1 < N) {
+          if (world[i + 1][j] == 1)
+            neighbors++;
+          if (j - 1 >= 0)
+            if (world[i + 1][j - 1] == 1)
+              neighbors++;
+          if (j + 1 < N)
+            if (world[i + 1][j + 1] == 1)
+              neighbors++;
+        }
+        //To the side of us same row
+        if(j + 1 < N)
+          if(world[i][j+1]==1)
+            neighbors++;
+        if(j - 1 >= 0)
+          if(world[i][j-1]==1)
+            neighbors++;
+        //If neighbors are to many or few i die.
+
+        ///We Are Segfaulting here because C is only size N/size not j*size/rank
+        //cout << "k: " << k << " C[k]: " << C[k] << " World[i][j] " << world[i][j] <<  " rank: " << rank <<endl;
+        if(neighbors > 3 || neighbors <2)
+          C[k]=0;
+          //If my neighbors = 2/3 I live, or if I am dead and neighbors = 3 I come alive.
+        else if(neighbors == 3){
+          C[k]=1;
+        }else{
+          C[k]=world[i][j];
+        }
+      }
+      //cout << "ABOVE BARRIER" << endl;
+      MPI_Barrier(MCW);
+      //Gather all of it back up.
+      cout << "above gather !!!!!!!!!!!!!!!" << endl;
+      MPI_Gather (&C[0], N/size, MPI_INT, &world[i][0], N/size, MPI_INT, 0, MCW);
+
+
+    }
+    if(rank == 0){
+      for(int x = 0; x < N; x++){
+        for( int y = 0; y < N; y++){
+          cout << world[x][y] << " ";
+        }
+        cout << endl;
+      }
+      cout << endl << endl << endl;
+      finished = true;
+      for( int i = 0; i<N*N; i++){
+        if(worldData[i]!=0)
+          finished = false;
+      }
+    }
+  }while(!finished);
+
+  MPI_Finalize();
+}