segfaultfix

assignments/03/.gitignore

@@ -2,3 +2,4 @@ lpa
 compile_commands.json
 .cache
 report.pdf
+*.tar.gz

assignments/03/Makefile

@@ -1,13 +1,14 @@
 .PHONY: run clean
 
-CFLAGS += -DFMT_HEADER_ONLY
-LDFLAGS += $(shell pkg-config --libs fmt)
+CFLAGS += -O3 -g
+# CFLAGS += -DFMT_HEADER_ONLY 
+# LDFLAGS += $(shell pkg-config --libs fmt)
 
 clean:
 	rm -f lpa
 
 lpa: lpa.cpp
-	mpic++ $(CFLAGS) $(LDFLAGS) -o $@ -g $<
+	mpic++ $(CFLAGS) $(LDFLAGS) -o $@ $<
 
 run:
 	watchexec -c clear 'make lpa && mpirun -n 4 ./lpa dataset/both_1000.txt'

assignments/03/lpa.cpp

@@ -27,6 +27,15 @@ typedef struct {
 } pair;
 void init_pair_type(MPI_Datatype *out);
 
+struct pair_vector {
+  pair *ptr;
+  int cap;
+  int len;
+};
+void pair_vector_init(struct pair_vector *);
+void pair_vector_clear(struct pair_vector *);
+void pair_vector_push(struct pair_vector *v, int fst, int snd);
+
 int main(int argc, char **argv) {
   MPI::Init(argc, argv);
   int rank = MPI::COMM_WORLD.Get_rank(), p = MPI::COMM_WORLD.Get_size();
@@ -75,7 +84,9 @@ int main(int argc, char **argv) {
   int counts[p], displs[p];
   if (rank == 0) {
     line = NULL;
-    pair all_edges[total_num_edges];
+    // pair all_edges[total_num_edges];
+    struct pair_vector all_edges;
+    pair_vector_init(&all_edges);
 
     // For the current process, what's the last node we're expecting to see?
     int current_process = 0;
@@ -92,11 +103,11 @@ int main(int argc, char **argv) {
         if (current_process == 0) {
           num_my_edges = edge_counter;
           my_edges = (pair *)calloc(num_my_edges, sizeof(pair));
-          memcpy(my_edges, all_edges, edge_counter * sizeof(pair));
+          memcpy(my_edges, all_edges.ptr, edge_counter * sizeof(pair));
         } else {
           MPI_Send(&edge_counter, 1, MPI_INT, current_process,
                    TAG_SEND_NUM_EDGES, MPI::COMM_WORLD);
-          MPI_Send(all_edges, edge_counter, IntPairType, current_process,
+          MPI_Send(all_edges.ptr, edge_counter, IntPairType, current_process,
                    TAG_SEND_EDGES, MPI::COMM_WORLD);
         }
 
@@ -104,11 +115,10 @@ int main(int argc, char **argv) {
         current_process += 1;
         current_node_range = node_range(current_process);
         edge_counter = 0;
+        pair_vector_clear(&all_edges);
       }
 
-      all_edges[edge_counter].fst = fst;
-      all_edges[edge_counter].snd = snd;
-
+      pair_vector_push(&all_edges, fst, snd);
       edge_counter += 1;
     }
 
@@ -116,18 +126,8 @@ int main(int argc, char **argv) {
     // the loop above
     MPI_Send(&edge_counter, 1, MPI_INT, current_process, TAG_SEND_NUM_EDGES,
              MPI::COMM_WORLD);
-    MPI_Send(all_edges, edge_counter, IntPairType, current_process,
+    MPI_Send(all_edges.ptr, edge_counter, IntPairType, current_process,
              TAG_SEND_EDGES, MPI::COMM_WORLD);
-
-    // int step = num_edges / p;
-    // for (int i = 0; i < p; ++i) {
-    //   int start = i * step;
-    //   int end = i == p - 1 ? num_edges : start + step;
-    //   int count = end - start;
-
-    //   counts[i] = count;
-    //   displs[i] = start;
-    // }
   } else {
     MPI_Recv(&num_my_edges, 1, MPI_INT, 0, TAG_SEND_NUM_EDGES, MPI::COMM_WORLD,
              NULL);
@@ -316,8 +316,10 @@ int main(int argc, char **argv) {
   MPI::COMM_WORLD.Barrier();
   double end_time = MPI::Wtime();
 
+  if (rank == 0) {
     printf("2-5 Time: %0.04fs\n", end_time - step_2_start_time);
     printf("5 Time: %0.04fs\n", end_time - step_5_start_time);
+  }
 
 // The results are gathered to a single process, which writes them to the
 // disk.
@@ -370,3 +372,29 @@ void init_pair_type(MPI_Datatype *out) {
   MPI_Type_create_struct(2, blocklengths, offsets, types, out);
   MPI_Type_commit(out);
 }
+
+void pair_vector_init(struct pair_vector *v) {
+  const int INITIAL = 100;
+  v->ptr = (pair *)malloc(INITIAL * sizeof(pair));
+  v->cap = INITIAL;
+  v->len = 0;
+}
+
+void pair_vector_clear(struct pair_vector *v) { v->len = 0; }
+
+void pair_vector_push(struct pair_vector *v, int fst, int snd) {
+  if (v->len == v->cap) {
+    v->cap *= 2;
+    pair *new_loc = (pair *)malloc(v->cap * sizeof(pair));
+    for (int i = 0; i < v->len; ++i) {
+      new_loc[i].fst = v->ptr[i].fst;
+      new_loc[i].snd = v->ptr[i].snd;
+    }
+    free(v->ptr);
+    v->ptr = new_loc;
+  }
+
+  v->ptr[v->len].fst = fst;
+  v->ptr[v->len].snd = snd;
+  v->len++;
+}