From 1ff1618017994332da265be161e8cc548e8b8495 Mon Sep 17 00:00:00 2001
From: David Phillips <dbphillipsnz@gmail.com>
Date: Fri, 24 Jul 2015 13:01:44 +1200
Subject: Started work on cluster-style parallel processing

---
 algorithms/mandelbrot.c |  2 +-
 fractal-gen.c           | 18 ++++++++++++++----
 fractal-gen.h           |  2 ++
 3 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/algorithms/mandelbrot.c b/algorithms/mandelbrot.c
index 3b10b0a..1c3f5a2 100644
--- a/algorithms/mandelbrot.c
+++ b/algorithms/mandelbrot.c
@@ -40,7 +40,7 @@ void *generate_mandelbrot_section(void *section)
 
 	for (y = d->core, b = (d->core*(size_units/d->size)+top); y < d->size; b+=((d->cores*size_units)/d->size), y+=d->cores)
 	{
-		for (x = 0, a = left; x < d->size; a+=(size_units/d->size), x++)
+		for (x = d->clust_id, a = (d->clust_id*(size_units/d->size)+left); x < d->size; a+=((d->clust_total*size_units)/d->size), x+=d->clust_total)
 		{
 			z = 0;
 			c = a+I*b;
diff --git a/fractal-gen.c b/fractal-gen.c
index 02ec5bd..b2025a9 100644
--- a/fractal-gen.c
+++ b/fractal-gen.c
@@ -36,6 +36,7 @@ struct section_generator
 int main(int argc, char **argv)
 {
 	unsigned int size, iterat, cores, i, x, y;
+	unsigned int clust_id, clust_total;
 	double power;
 	char* bname;
 	data_section* sections;
@@ -61,9 +62,10 @@ int main(int argc, char **argv)
 		return EXIT_FAILURE;
 	}
 
-	if (argc != 4 && argc != 5)
+	if (argc != 4 && argc != 5 && argc != 6)
 	{
-		fprintf(stderr, "%s size iterat power [threads]\n", argv[0]);
+		fprintf(stderr, "%s size iterat power [threads]\n"
+		                "%s size iterat power [cluster id] [cluster total]\n", argv[0], argv[0]);
 		return EXIT_FAILURE;
 	}
 
@@ -71,8 +73,14 @@ int main(int argc, char **argv)
 	iterat = atoi(argv[2]);
 	power  = atof(argv[3]);
 
-	// Fetch number of cores available on machine
+	/* Fetch or use defaults for
+	 * - num cores available
+	 * - our ID in cluster
+	 * - total members in cluster
+	 */
 	cores = argc == 5? atoi(argv[4]) : sysconf(_SC_NPROCESSORS_ONLN); 	// Screw maintainability ;)
+	clust_id = argc == 6? atoi(argv[4]) : 0;
+	clust_total = argc == 6? atoi(argv[5]) : 1;
 
 	// Interlacing is column-based, can't have more workers than columns
 	if (cores > size)
@@ -99,6 +107,8 @@ int main(int argc, char **argv)
 		// Has to be a better way
 		sections[i].core = i;
 		sections[i].cores = cores;
+		sections[i].clust_id = clust_id;
+		sections[i].clust_total = clust_total;
 		sections[i].size = size;
 		sections[i].power = power;
 		sections[i].iterat = iterat;
@@ -131,7 +141,7 @@ int main(int argc, char **argv)
 
 
 	// Output PGM Header
-	printf("P5\n%d\n%d\n255\n",size,size);
+	printf("P5\n%d\n%d\n255\n",size/clust_total,size);
 
 	// Vomit the data segments back onto the screen, deinterlacing
 	// TO DO: look at fwrite performance benefits over putchar
diff --git a/fractal-gen.h b/fractal-gen.h
index 3c4e435..656aeec 100644
--- a/fractal-gen.h
+++ b/fractal-gen.h
@@ -42,6 +42,8 @@ typedef struct
 {
 	unsigned int core;
 	unsigned int cores;
+	unsigned int clust_id;
+	unsigned int clust_total;
 	unsigned int size;
 	double power;
 	unsigned int iterat;
-- 
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