good progress

assignments/02/process_output.py

@@ -21,4 +21,6 @@ for p in sorted(outputs.keys()):
     print(f"---- {p} ----")
     for line in lines:
         print(line)
-    print()
+    print()
+
+print("Done.")

assignments/02/qs_mpi.c

@@ -18,6 +18,7 @@
 
 void local_quicksort(int *arr, int lo, int hi);
 char *string_of_list(int *arr, int len);
+void recursive_quicksort(int *integers, int n, MPI_Comm comm);
 
 int main(int argc, char **argv) {
   int rank, p;
@@ -45,7 +46,80 @@ int main(int argc, char **argv) {
     // printf(" - %d\n", integers[i]);
   }
 
-  int group_root = 0;
+  recursive_quicksort(integers, n, MPI_COMM_WORLD);
+
+  sleep(1);
+  printf("[%d] after: %s\n", rank, string_of_list(integers, n_over_p));
+
+  // The first node is responsible for collecting all the data and then
+  // printing it out to the file MPI_Gather(const void *sendbuf, int
+  // sendcount, MPI_INT, void *recvbuf,
+  //            int recvcount, MPI_INT, 0, MPI_COMM_WORLD);
+  if (rank == 0) {
+    FILE *f = fopen(argv[2], "w");
+    fclose(f);
+  }
+
+  MPI_Finalize();
+  printf("Done.\n");
+  return 0;
+}
+
+// hi not inclusive
+void local_quicksort(int *arr, int lo, int hi) {
+  int temp;
+
+  if (lo >= hi || lo < 0)
+    return;
+
+  int pivot = arr[hi - 1];
+  int pivot_idx = lo - 1;
+  for (int j = lo; j < hi; ++j) {
+    if (arr[j] < pivot) {
+      pivot_idx += 1;
+
+      temp = arr[j];
+      arr[j] = arr[pivot_idx];
+      arr[pivot_idx] = temp;
+    }
+  }
+
+  pivot_idx += 1;
+  temp = arr[hi - 1];
+  arr[hi - 1] = arr[pivot_idx];
+  arr[pivot_idx] = temp;
+
+  // Recursive call
+  local_quicksort(arr, lo, pivot_idx);
+  local_quicksort(arr, pivot_idx + 1, hi);
+}
+
+char *string_of_list(int *arr, int len) {
+  char *buffer = calloc(sizeof(char), 1000);
+  int offset = 0; // Keep track of the current position in the buffer
+  for (int i = 0; i < len; i++) {
+    offset += sprintf(buffer + offset, "%d", arr[i]);
+    if (i < len - 1) {
+      // Add a separator (e.g., comma or space) if it's not the last element
+      offset += sprintf(buffer + offset, " ");
+    }
+  }
+
+  return buffer;
+}
+
+void recursive_quicksort(int *integers, int n, MPI_Comm comm) {
+  int rank, p;
+  MPI_Comm_size(comm, &p);
+  MPI_Comm_rank(comm, &rank);
+
+  if (p == 1) {
+    // Recursion base case: just sort it serially
+    local_quicksort(integers, 0, n);
+    return;
+  }
+
+  int n_over_p = n / p;
 
   // Locally sort
   // printf("[%d] Numbers before:           %s\n", rank,
@@ -62,7 +136,7 @@ int main(int argc, char **argv) {
   // Not the real median though, need an existing element of the array
   pivot = integers[n_over_p / 2];
   MPI_Bcast(&pivot, 1, MPI_INT, 0, MPI_COMM_WORLD);
-  printf("--- Broadcasted pivot: %d ---\n", pivot);
+  // printf("--- Broadcasted pivot: %d ---\n", pivot);
 
   // Determine where the boundary between S (lower) and L (higher) lies
   int boundary;
@@ -79,10 +153,14 @@ int main(int argc, char **argv) {
          S_size, L_lo, L_hi, L_size);
 
   // Perform global arrangement
-  int S_global_end, L_reverse_end;
+  int S_global_end, L_reverse_end, S_global_max_end;
   MPI_Scan(&S_size, &S_global_end, 1, MPI_INT, MPI_SUM, MPI_COMM_WORLD);
   MPI_Scan(&L_size, &L_reverse_end, 1, MPI_INT, MPI_SUM, MPI_COMM_WORLD);
 
+  // printf("[%d] bruh %d\n", rank, S_global_end);
+  MPI_Reduce(&S_global_end, &S_global_max_end, 1, MPI_INT, MPI_MAX, 0,
+             MPI_COMM_WORLD);
+
   int S_global_start = S_global_end - S_size,
       L_reverse_start = L_reverse_end - L_size,
       L_global_start = n - L_reverse_end, L_global_end = n - L_reverse_start;
@@ -253,62 +331,37 @@ int main(int argc, char **argv) {
     }
   }
 
-  sleep(1);
-  printf("[%d] after: %s\n", rank, string_of_list(integers, n_over_p));
+  // Now, determine which processes should be responsible for taking the S and L
+  // arrays
 
-  // The first node is responsible for collecting all the data and then
-  // printing it out to the file MPI_Gather(const void *sendbuf, int
-  // sendcount, MPI_INT, void *recvbuf,
-  //            int recvcount, MPI_INT, 0, MPI_COMM_WORLD);
+  // Specifically, the part where it's split, break the tie to see if it goes
+  // down or up
+  int colors[p];
   if (rank == 0) {
-    FILE *f = fopen(argv[2], "w");
-    fclose(f);
-  }
+    int p_of_split = S_global_max_end / n_over_p;
+    int split_point = S_global_max_end % n_over_p;
+    printf("[%d] shiet %d\n", rank, p_of_split);
 
-  MPI_Finalize();
-  printf("Done.\n");
-  return 0;
-}
+    int lo_start = 0, lo_end;
+    int hi_start, hi_end = p;
+    if (split_point > n_over_p / 2) {
+      // Belongs to the lower group
+      lo_end = hi_start = p_of_split + 1;
+    } else {
+      // Belongs to the higher group
+      lo_end = hi_start = p_of_split;
+    }
 
-// hi not inclusive
-void local_quicksort(int *arr, int lo, int hi) {
-  int temp;
-
-  if (lo >= hi || lo < 0)
-    return;
-
-  int pivot = arr[hi - 1];
-  int pivot_idx = lo - 1;
-  for (int j = lo; j < hi; ++j) {
-    if (arr[j] < pivot) {
-      pivot_idx += 1;
-
-      temp = arr[j];
-      arr[j] = arr[pivot_idx];
-      arr[pivot_idx] = temp;
+    for (int i = 0; i < p; ++i) {
+      if (i < lo_end)
+        colors[i] = 100;
+      else
+        colors[i] = 200;
     }
   }
 
-  pivot_idx += 1;
-  temp = arr[hi - 1];
-  arr[hi - 1] = arr[pivot_idx];
-  arr[pivot_idx] = temp;
-
-  // Recursive call
-  local_quicksort(arr, lo, pivot_idx);
-  local_quicksort(arr, pivot_idx + 1, hi);
-}
-
-char *string_of_list(int *arr, int len) {
-  char *buffer = calloc(sizeof(char), 1000);
-  int offset = 0; // Keep track of the current position in the buffer
-  for (int i = 0; i < len; i++) {
-    offset += sprintf(buffer + offset, "%d", arr[i]);
-    if (i < len - 1) {
-      // Add a separator (e.g., comma or space) if it's not the last element
-      offset += sprintf(buffer + offset, " ");
-    }
-  }
-
-  return buffer;
+  MPI_Comm child;
+  MPI_Comm_split(comm, colors[rank], rank, &child);
+  printf("[%d] Recursing...\n", rank);
+  MPI_Comm_free(&child);
 }