From 60d9bb61789268076c47a4c69bbedf383359e57c Mon Sep 17 00:00:00 2001
From: josh <josh@45c1a28c-8058-47b2-ae61-ca45b979098e>
Date: Mon, 8 Dec 2008 18:05:41 +0000
Subject: [PATCH] added some comments; restored printing # of cores on MPI node
 #0

git-svn-id: svn://anubis/gvsu@337 45c1a28c-8058-47b2-ae61-ca45b979098e
---
 cs677/final/mpi-fractals.cc | 32 +++++++++++++++++++++++++++++---
 1 file changed, 29 insertions(+), 3 deletions(-)

diff --git a/cs677/final/mpi-fractals.cc b/cs677/final/mpi-fractals.cc
index 3f1ef4f..5de6339 100644
--- a/cs677/final/mpi-fractals.cc
+++ b/cs677/final/mpi-fractals.cc
@@ -1,7 +1,9 @@
 /*
  * Josh Holtrop
  * 2008-12-11
- * barebones SDL program
+ * CS677 Final Project
+ * This program implements a fractal-image generator and viewer
+ * that uses OpenMPI and OpenMP.
  */
 
 #include <SDL/SDL.h>
@@ -18,6 +20,9 @@ using namespace std;
 #define getXVirt(x) (((x) - (width >> 1)) * zoom + x_center)
 #define getYVirt(y) ((-((y) - (height >> 1))) * zoom + y_center)
 
+/**************************************************************************
+ * Utility functions                                                      *
+ *************************************************************************/
 bool createWindow(int width, int height,
                   SDL_Surface ** screen, Uint32 ** pixels);
 void getSizes(int * rank, int * size, int * nprocs);
@@ -25,12 +30,18 @@ void draw(int rank, int world_size, int nprocs, int width, int height,
     Uint32 * pixels, Uint32 * taskVals, Computation * computation);
 void sendWindowVals(double * winVals, int world_size);
 
+/**************************************************************************
+ * Global variables                                                       *
+ *************************************************************************/
 static double x_center = 0.0;
 static double y_center = 0.0;
 static double zoom = 1/300.0;
 /* a "task" will be processing task_size pixels */
 static int task_size = 100;
 
+/**************************************************************************
+ * This is the main entry point for our program                           *
+ *************************************************************************/
 int main(int argc, char * argv[])
 {
     int width = 600;
@@ -203,6 +214,10 @@ int main(int argc, char * argv[])
     return 0;
 }
 
+/**************************************************************************
+ * This utility function is used by the master MPI node to create a       *
+ * window using SDL for displaying the fractal in and getting user input. *
+ *************************************************************************/
 bool createWindow(int width, int height,
                   SDL_Surface ** screen, Uint32 ** pixels)
 {
@@ -226,6 +241,10 @@ bool createWindow(int width, int height,
     return true;
 }
 
+/**************************************************************************
+ * This utility function returns the MPI node's rank, the total number    *
+ * of MPI nodes, and the number of processing cores on the local node     *
+ *************************************************************************/
 void getSizes(int * rank, int * size, int * nprocs)
 {
     MPI_Comm_rank(MPI_COMM_WORLD, rank);
@@ -249,8 +268,7 @@ void getSizes(int * rank, int * size, int * nprocs)
     {
         int total_nprocs = 0;
         cout << "Number of cores on each MPI node:" << endl;
-        int i = (*size > 1) ? 1 : 0;
-        for (; i < *size; i++)
+        for (int i = 0; i < *size; i++)
         {
             cout << all_nprocs[i] << " ";
             total_nprocs += all_nprocs[i];
@@ -260,6 +278,10 @@ void getSizes(int * rank, int * size, int * nprocs)
     }
 }
 
+/**************************************************************************
+ * This function is executed by each MPI node every time a fractal        *
+ * frame is to be drawn.                                                  *
+ *************************************************************************/
 void draw(int rank, int world_size, int nprocs, int width, int height,
     Uint32 * pixels, Uint32 * taskVals, Computation * computation)
 {
@@ -341,6 +363,10 @@ void draw(int rank, int world_size, int nprocs, int width, int height,
     }
 }
 
+/**************************************************************************
+ * This utility function is used by the master process to update all      *
+ * of the slave processes for the position and zoom-level of the view.    *
+ *************************************************************************/
 void sendWindowVals(double * winVals, int world_size)
 {
     // DEBUG: