From 51e793af96f5f27176af26e165d9fa709a455299 Mon Sep 17 00:00:00 2001
From: Fabio Salvini <salvini.fabio001@gmail.com>
Date: Sat, 12 Nov 2016 15:38:02 +0100
Subject: [PATCH] Added sequential version

---
 config/config.c                | 58 +++++++++++++++++++++++++++++
 config/config.h                | 11 ++++++
 sequential/Makefile            | 12 ++++++
 sequential/jacobi.conf         | 16 ++++++++
 sequential/jacobi_sequential.c | 68 ++++++++++++++++++++++++++++++++++
 5 files changed, 165 insertions(+)
 create mode 100644 config/config.c
 create mode 100644 config/config.h
 create mode 100644 sequential/Makefile
 create mode 100644 sequential/jacobi.conf
 create mode 100644 sequential/jacobi_sequential.c

diff --git a/config/config.c b/config/config.c
new file mode 100644
index 0000000..7d1c1b7
--- /dev/null
+++ b/config/config.c
@@ -0,0 +1,58 @@
+#include <stdio.h>
+#include <string.h>
+
+typedef struct configuration {
+  int n;
+  double north;
+  double east;
+  double south;
+  double west;
+  double init_value;
+  double threshold;
+} configuration;
+
+int load_config(configuration *config) {
+  char property[100];
+  char *value;
+  FILE *fp;
+
+  fp = fopen("jacobi.conf", "r");
+  if (fp == NULL) {
+    perror("Error opening file jacobi.conf");
+    return 1;
+  }
+  while (fgets(property, 100, fp) != NULL) {
+    if (property[0] == '\n' || property[0] == '#') {
+      /* Skip empty lines and comments */
+      continue;
+    }
+    value = strchr(property, ' ');
+    if (value == NULL) {
+      fclose(fp);
+      perror("Error reading file jacobi.conf");
+      return 1;
+    }
+    value[0] = '\0';
+    value += sizeof(char);
+    value[strlen(value) - 1] = '\0';
+    if (strcmp(property, "N") == 0) {
+      sscanf(value, "%d", &(config->n));
+    } else if (strcmp(property, "NORTH") == 0) {
+      sscanf(value, "%lf", &(config->north));
+    } else if (strcmp(property, "EAST") == 0) {
+      sscanf(value, "%lf", &(config->east));
+    } else if (strcmp(property, "SOUTH") == 0) {
+      sscanf(value, "%lf", &(config->south));
+    } else if (strcmp(property, "WEST") == 0) {
+      sscanf(value, "%lf", &(config->west));
+    } else if (strcmp(property, "INIT_VALUE") == 0) {
+      sscanf(value, "%lf", &(config->init_value));
+    } else if (strcmp(property, "THRESHOLD") == 0) {
+      sscanf(value, "%lf", &(config->threshold));
+    } else {
+      printf("Unknown property %s\n", property);
+    }
+  }
+  fclose(fp);
+  return 0;
+}
diff --git a/config/config.h b/config/config.h
new file mode 100644
index 0000000..32635dd
--- /dev/null
+++ b/config/config.h
@@ -0,0 +1,11 @@
+typedef struct configuration {
+  int n;
+  double north;
+  double east;
+  double south;
+  double west;
+  double init_value;
+  double threshold;
+} configuration;
+
+int load_config(configuration *config);
diff --git a/sequential/Makefile b/sequential/Makefile
new file mode 100644
index 0000000..aacf23e
--- /dev/null
+++ b/sequential/Makefile
@@ -0,0 +1,12 @@
+CC=gcc
+CFLAGS=-Wall -lm -std=c99
+
+all: config jacobi_sequential.c
+	${CC} ${CFLAGS} config.o jacobi_sequential.c -o jacobi.out
+
+config: ../config/config.c
+	${CC} -c ${CFLAGS} ../config/config.c
+
+.PHONY: clean
+clean:
+	rm -f *.out *.o
diff --git a/sequential/jacobi.conf b/sequential/jacobi.conf
new file mode 100644
index 0000000..95ce868
--- /dev/null
+++ b/sequential/jacobi.conf
@@ -0,0 +1,16 @@
+# Configuration file for the Jacobi project.
+
+# The size of the matrix (borders excluded).
+N 10
+
+# The value at each border.
+NORTH 0.0
+EAST 0.0
+SOUTH 300.0
+WEST 0.0
+
+# The initial value to assign at each internal cell.
+INIT_VALUE 0.0
+
+# The threshold that determines the convergence.
+THRESHOLD 1.0
diff --git a/sequential/jacobi_sequential.c b/sequential/jacobi_sequential.c
new file mode 100644
index 0000000..6061dce
--- /dev/null
+++ b/sequential/jacobi_sequential.c
@@ -0,0 +1,68 @@
+/*
+ * Sequential version.
+ * No paralleliization used.
+ */
+
+#include <stdio.h>
+#include <math.h>
+#include "../config/config.h"
+
+typedef struct borders {
+  double north;
+  double east;
+  double south;
+  double west;
+} borders;
+
+void compute_jacobi(int n, double init_value, double threshold, borders b);
+
+int main(int argc, char* argv[]) {
+  int config_loaded;
+  configuration config;
+  borders b;
+
+  config_loaded = load_config(&config);
+  if (config_loaded != 0) {
+    return 1;
+  }
+
+  b.north = config.north;
+  b.east = config.east;
+  b.south = config.south;
+  b.west = config.west;
+
+  compute_jacobi(config.n, config.init_value, config.threshold, b);
+
+  return 0;
+}
+
+void compute_jacobi(int n, double init_value, double threshold, borders b) {
+  double x[n + 2][n + 2];
+  double max_diff, new_x;
+  int i, j;
+
+  /* Initialize boundary regions */
+  for (i = 1; i <= n; i++) {
+    x[0][i] = b.north;
+    x[n + 1][i] = b.south;
+    x[i][0] = b.west;
+    x[i][n + 1] = b.east;
+  }
+  /* Initialize the rest of the matrix */
+  for (i = 1; i <= n; i++) {
+    for (j = 1; j <= n; j++) {
+      x[i][j] = init_value;
+    }
+  }
+  /* Iterative refinement of x until values converge */
+  do {
+    max_diff = 0;
+    for (i = 1; i <= n; i++) {
+      for (j = 1; j <= n; j++) {
+        new_x = 0.25 * (x[i - 1][j] + x[i][j + 1] + x[i + 1][j] + x[i][j - 1]);
+        max_diff = (double) fmax(max_diff, fabs(new_x - x[i][j]));
+        x[i][j] = new_x;
+      }
+    }
+  } while (max_diff > threshold);
+}