removed unnecessary memcpy's, minor improvements

cellular_automaton/c/configuration.c

@@ -5,6 +5,8 @@
 
 #include "configuration.h"
 
+#define MAX_ITERATIONS 100
+
 const char *verbosity_levels[] = {"OFF", "INFO", "DEBUG", "TRACE"};
 
 const char *communication_computation_modes[] = {
@@ -80,6 +82,15 @@ void conf_init_from_args(conf_t *c, int argc, char* argv[])
       }
    }
 
+   if(c->n_iterations > MAX_ITERATIONS) {
+      fprintf(stderr,
+         "Specified number of iterations, %d, exceeds maximum of %d.\n"
+         "(One output file will be generated for each iteration)\n",
+         c->n_iterations, MAX_ITERATIONS
+      );
+      MPI_Abort(MPI_COMM_WORLD, EXIT_FAILURE);
+   }
+
    if(optind > argc) {
       fprintf(stderr, "Expected base name of input file (omitting '.wi' file extension)\n");
       MPI_Abort(MPI_COMM_WORLD, EXIT_FAILURE);

cellular_automaton/c/main.c

@@ -103,8 +103,9 @@ void iterate(const conf_t *c, world_t *world)
    size_t header_length;
 
    if(info_enabled(c)) printf(
-      "Running %d iterations with %ld generations per iteration.\n\n",
-      n_it, n_gen
+      "Running %d iteration%s with %ld generation%s per iteration.\n\n",
+      n_it,  n_it  == 1 ? "" : "s",
+      n_gen, n_gen == 1 ? "" : "s"
    );
 
    total_time = -MPI_Wtime();

cellular_automaton/c/simulation.c

@@ -201,27 +201,23 @@ void do_simulation_persistent_request_no_overlap(world_t *world, size_t n_genera
    const size_t sz = world_get_storage_size(world);
 
    size_t g, i;
-   char *tmp = malloc(sz);
    MPI_Request *requests = world->transfer.persistent_requests;
 
    for(g = 0; g < n_generations; g++) {
 
       // Persistent send/receive requests have been initialized with pointer to world->cell_prev.
-      // Swapping pointers here will therefore not work and swapping memory is necessary.
+      // Swapping pointers here will therefore not work and copying memory is necessary.
       //
       // Possible Optimization:
       // ----------------------
       // Alternately using two sets of persistent requests (one for world->cells_prev and world->cells_next).
-      memcpy(tmp, world->cells_prev, sz);
       memcpy(world->cells_prev, world->cells_next, sz);
-      memcpy(world->cells_next, tmp, sz);
 
       MPI_Startall(2*n_neighbors, requests);
       MPI_Waitall(2*n_neighbors, requests, MPI_STATUSES_IGNORE);
 
       wireworld_step_complete(world);
    }
-   free(tmp);
 }
 
 void do_simulation_persistent_request_overlap(world_t *world, size_t n_generations)
@@ -230,16 +226,12 @@ void do_simulation_persistent_request_overlap(world_t *world, size_t n_generatio
    const size_t sz = world_get_storage_size(world);
 
    size_t g, i;
-   char *tmp = malloc(sz);
-
    MPI_Request *requests = world->transfer.persistent_requests;
 
    for(g = 0; g < n_generations; g++) {
 
       // See above note in the '_no_overlap' funciton.
-      memcpy(tmp, world->cells_prev, sz);
       memcpy(world->cells_prev, world->cells_next, sz);
-      memcpy(world->cells_next, tmp, sz);
 
       MPI_Startall(2*n_neighbors, requests);
 
@@ -249,7 +241,6 @@ void do_simulation_persistent_request_overlap(world_t *world, size_t n_generatio
 
       wireworld_step_boundary(world);
    }
-   free(tmp);
 }
 
 void wireworld_step_complete(world_t *world)