[DRAFT] SENPAI Parallel computing #9 -- MPI implementation

Makefile

@@ -6,22 +6,18 @@
 
 .PHONY: all clean fclean re
 
-$(CC) := gcc
-
 SRC_DIR := ./sources
 HDR_DIR := ./headers
 
 SRCS := $(shell find $(SRC_DIR) -name "*.c")
 OBJS := $(shell find $(SRC_DIR) -name "*.o")
 NAME := senpai
 
-WARNINGS := -Wall -Wextra -Wshadow -Wpointer-arith -Wcast-align -Wwrite-strings -Wmissing-prototypes -Wmissing-declarations -Wredundant-decls -Wnested-externs -Winline -Wno-long-long -Wuninitialized -Wstrict-prototypes
-OPTIONS := -std=c99 -O2 -g -U__STRICT_ANSI__
 LIBS := -lm
-CFLAGS := -I$(HDR_DIR) $(WARNINGS) $(OPTIONS) $(LIBS) -o $(NAME).bin
+CFLAGS := -I$(HDR_DIR) $(WARNINGS) $(OPTIONS) $(LIBS) -o $(NAME)mpi.bin
 
 all:
-	$(CC) $(SRCS) $(CFLAGS)
+	mpicc $(SRCS) $(CFLAGS)
 
 clean:
 	$(RM) $(OBJS)

sources/main.c

@@ -15,16 +15,38 @@
 #include "text.h"
 #include "util.h"
 
+#include <mpi.h>
+
+#define MIN(X, Y) (((X) < (Y)) ? (X) : (Y))
+#define MODE_NUMERICAL           1
+
+
 int main(int argc, char **argv)
 {
+  // Initializare MPI
+  MPI_Init(&argc, &argv);
+
   args_t args;         /* Program arguments (from argv) */
   universe_t universe; /* The universe itself (wow) */
 
   /* We don't need a perfectly random generator */
   // srand((unsigned int)time(NULL));
 
+
+  // Get the number of processes
+  int world_size;
+  MPI_Comm_size(MPI_COMM_WORLD, &world_size);
+
+  // Get the rank of the process
+  int world_rank;
+  MPI_Comm_rank(MPI_COMM_WORLD, &world_rank);
+
+
+
   /* That's the welcome message */
-  puts(TEXT_START);
+  if(world_rank == 0) {
+    puts(TEXT_START);
+  }
 
   /* Parse the arguments */
   args_init(&args);
@@ -44,5 +66,107 @@ int main(int argc, char **argv)
     return (retstri(EXIT_FAILURE, TEXT_MAIN_FAILURE, __FILE__, __LINE__));
 
   /* Let's roll */
-  return (universe_simulate(&universe, &args));
+
+  // universe_simulate(&universe, &args);
+  uint64_t frame_nb; /* Used for frameskipping */
+
+  /* Tell the user the simulation is starting */
+  puts(TEXT_SIMSTART);
+
+  /* While we haven't reached the target time, we iterate the universe */
+  frame_nb = 0;
+
+
+        // Impartim numarul la cate procese avem
+        int ratio = universe.atom_nb/world_size;
+        int start = world_rank * ratio;
+        int end = (world_rank + 1) * ratio;
+
+      // Daca e ultimul proces, atunci merge pana la final
+      if (world_rank == world_size - 1)
+        end = universe.atom_nb;
+
+  while (universe.time < args.max_time)
+  {
+    if(world_rank == 0) {
+      /* Print the state to the .xyz file, if required */
+     if (!frame_nb)
+     {
+       universe_printstate(&universe);
+       frame_nb = (args.frameskip);
+     }
+     else
+       --frame_nb;
+   }
+    /* Iterate */
+    // 
+    // universe_iterate(universe, args)
+    size_t i; /* Iterator */
+
+    /* We update the position vector first, as part of the Velocity-Verley integration */
+    for (i=0; i<(universe.atom_nb); ++i)
+      if (atom_update_pos(&universe, &args, i) == NULL)
+        return (retstr(NULL, TEXT_UNIVERSE_ITERATE_FAILURE, __FILE__, __LINE__));
+
+    /* We enforce the periodic boundary conditions */
+
+    for (i=0; i<(universe.atom_nb); ++i)
+      if (atom_enforce_pbc(&universe, i) == NULL)
+        return (retstr(NULL, TEXT_UNIVERSE_ITERATE_FAILURE, __FILE__, __LINE__));
+
+    /* Update the force vectors */
+    /* By numerically differentiating the potential energy... */
+    if (args.numerical == MODE_NUMERICAL)
+    {
+      for (i=0; i<(universe.atom_nb); ++i)
+        if (atom_update_frc_numerical(&universe, i) == NULL)
+          return (retstr(NULL, TEXT_UNIVERSE_ITERATE_FAILURE, __FILE__, __LINE__));
+    }
+
+    /* Or analytically solving for force */
+    else
+    {
+
+      for (i=start; i<end; ++i)
+        if (atom_update_frc_analytical(&universe, i) == NULL)
+          return (retstr(NULL, TEXT_UNIVERSE_ITERATE_FAILURE, __FILE__, __LINE__));
+    }
+
+    /* Update the acceleration vectors */
+    for (i=0; i<(universe.atom_nb); ++i)
+      if (atom_update_acc(&universe, i) == NULL)
+        return (retstr(NULL, TEXT_UNIVERSE_ITERATE_FAILURE, __FILE__, __LINE__));
+
+    /* Update the speed vectors */
+    for (i=0; i<(universe.atom_nb); ++i)
+      if (atom_update_vel(&universe, &args, i) == NULL)
+        return (retstr(NULL, TEXT_UNIVERSE_ITERATE_FAILURE, __FILE__, __LINE__));
+
+    // return (universe);
+
+    //TODO broadcast la universe.atom->pos - pentru toti atomii modificati de proces
+
+    double buf[3];
+    for (i=0; i<(universe.atom_nb); ++i){
+        buf[0] = universe.atom[i].pos.x;
+        buf[1] = universe.atom[i].pos.y;
+        buf[2] = universe.atom[i].pos.z;
+        MPI_Bcast(&buf, 3, MPI_DOUBLE, MIN(i/ratio, world_size - 1), MPI_COMM_WORLD);
+        universe.atom[i].pos.x = buf[0];
+        universe.atom[i].pos.y = buf[1];
+        universe.atom[i].pos.z = buf[2];
+    }
+    universe.time += args.timestep;
+    ++(universe.iterations);
+  }
+
+  /* End of simulation */
+  puts(TEXT_SIMEND);
+  universe_clean(&universe);
+
+  // Finalizare MPI
+  MPI_Finalize();
+
+  return 0;
+
 }

sources/universe.c

@@ -335,87 +335,6 @@ void universe_clean(universe_t *universe)
   free(universe->atom);
 }
 
-/* Main loop of the simulator. Iterates until the target time is reached */
-int universe_simulate(universe_t *universe, const args_t *args)
-{
-  uint64_t frame_nb; /* Used for frameskipping */
-
-  /* Tell the user the simulation is starting */
-  puts(TEXT_SIMSTART);
-
-  /* While we haven't reached the target time, we iterate the universe */
-  frame_nb = 0;
-  while (universe->time < args->max_time)
-  {
-    /* Print the state to the .xyz file, if required */
-    if (!frame_nb)
-    {
-      if (universe_printstate(universe) == NULL)
-        return (retstri(EXIT_FAILURE, TEXT_UNIVERSE_SIMULATE_FAILURE, __FILE__, __LINE__));
-      frame_nb = (args->frameskip);
-    }
-    else
-      --frame_nb;
-
-    /* Iterate */
-    if (universe_iterate(universe, args) == NULL)
-      return (retstri(EXIT_FAILURE, TEXT_UNIVERSE_SIMULATE_FAILURE, __FILE__, __LINE__));
-
-    universe->time += args->timestep;
-    ++(universe->iterations);
-  }
-
-  /* End of simulation */
-  puts(TEXT_SIMEND);
-  universe_clean(universe);
-
-  return (EXIT_SUCCESS);
-}
-
-universe_t *universe_iterate(universe_t *universe, const args_t *args)
-{
-  size_t i; /* Iterator */
-
-  /* We update the position vector first, as part of the Velocity-Verley integration */
-  for (i=0; i<(universe->atom_nb); ++i)
-    if (atom_update_pos(universe, args, i) == NULL)
-      return (retstr(NULL, TEXT_UNIVERSE_ITERATE_FAILURE, __FILE__, __LINE__));
-
-  /* We enforce the periodic boundary conditions */
-
-  for (i=0; i<(universe->atom_nb); ++i)
-    if (atom_enforce_pbc(universe, i) == NULL)
-      return (retstr(NULL, TEXT_UNIVERSE_ITERATE_FAILURE, __FILE__, __LINE__));
-
-  /* Update the force vectors */
-  /* By numerically differentiating the potential energy... */
-  if (args->numerical == MODE_NUMERICAL)
-  {
-    for (i=0; i<(universe->atom_nb); ++i)
-      if (atom_update_frc_numerical(universe, i) == NULL)
-        return (retstr(NULL, TEXT_UNIVERSE_ITERATE_FAILURE, __FILE__, __LINE__));
-  }
-
-  /* Or analytically solving for force */
-  else
-  {
-    for (i=0; i<(universe->atom_nb); ++i)
-      if (atom_update_frc_analytical(universe, i) == NULL)
-        return (retstr(NULL, TEXT_UNIVERSE_ITERATE_FAILURE, __FILE__, __LINE__));
-  }
-
-  /* Update the acceleration vectors */
-  for (i=0; i<(universe->atom_nb); ++i)
-    if (atom_update_acc(universe, i) == NULL)
-      return (retstr(NULL, TEXT_UNIVERSE_ITERATE_FAILURE, __FILE__, __LINE__));
-
-  /* Update the speed vectors */
-  for (i=0; i<(universe->atom_nb); ++i)
-    if (atom_update_vel(universe, args, i) == NULL)
-      return (retstr(NULL, TEXT_UNIVERSE_ITERATE_FAILURE, __FILE__, __LINE__));
-
-  return (universe);
-}
 
 /* Print the system's state to the .xyz file */
 universe_t *universe_printstate(universe_t *universe)