Add discussion of pipelines and branches

source-code/Branching/Makefile

@@ -1,9 +1,10 @@
 CFLAGS = -O2 -g -Wall -Wextra
+LDLIBS = -lm
 
 all: branch.exe
 
 %.exe: %.c
-	$(CC) $(CFLAGS) -o $@ $<
+	$(CC) $(CFLAGS) -o $@ $< $(LDLIBS)
 
 clean:
 	$(RM) *.exe *.o

source-code/Branching/branch.c

@@ -1,4 +1,5 @@
 #include <err.h>
+#include <math.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <sys/time.h>
@@ -13,11 +14,12 @@ double *init(int n) {
     return a;
 }
 
-double *init_cont(int n, int count) {
+double *init_cont(int n, double fraction) {
     int i;
     double *a = (double *) malloc(n*sizeof(double));
     if (a == NULL)
         errx(EXIT_FAILURE, "### error: can allocate %d double array", n);
+    int count = (int) ceil(fraction*n);
     for (i = 0; i < count; i++)
         a[i] = 0.1;
     for (i = count; i < n; i++)
@@ -30,52 +32,66 @@ long count_if(double *x, int n, int k) {
     int i, j;
     for (j = 0; j < k; j++)
         for (i = 0; i < n; i++)
-            if (x[i] < 0.5)
+            if (x[i] < 0.5) {
+                x[i] = log(sqrt(x[i]));
                 total++;
+            } else
+                x[i] = sqrt(-log(x[i]));
     return total;
 }
 
 long count_cond_expr(double *x, int n, int k) {
     long total = 0;
     int i, j;
     for (j = 0; j < k; j++)
-        for (i = 0; i < n; i++)
+        for (i = 0; i < n; i++) {
             total += x[i] < 0.5 ? 1 : 0;
+            x[i] = x[i] < 0.5 ? log(sqrt(x[i])) : sqrt(-log(x[i]));
+        }
     return total;
 }
 
 int main(int argc, char *argv[]) {
     int n = 100;
     int k = 100;
+    double fraction = 0.5;
     double *x;
     struct timeval tv1, tv2;
     long counter;
     if (argc > 1)
         n = atoi(argv[1]);
     if (argc > 2)
         k = atoi(argv[2]);
+    if (argc > 3)
+        fraction = atof(argv[3]);
+    printf("random assignment:\n");
     x = init(n);
     gettimeofday(&tv1, NULL);
     counter = count_if(x, n, k);
     gettimeofday(&tv2, NULL);
     printf("if condition:         %.6lf (%ld)\n",
             tv2.tv_sec - tv1.tv_sec + 1.0e-6*(tv2.tv_usec - tv1.tv_usec),
             counter);
+    free(x);
+    x = init(n);
     gettimeofday(&tv1, NULL);
     counter = count_cond_expr(x, n, k);
     gettimeofday(&tv2, NULL);
     printf("condition expression: %.6lf (%ld)\n",
             tv2.tv_sec - tv1.tv_sec + 1.0e-6*(tv2.tv_usec - tv1.tv_usec),
             counter);
     free(x);
-    x = init_cont(n, counter/k);
+    printf("%.3lf split:\n", fraction);
+    x = init_cont(n, fraction);
     gettimeofday(&tv1, NULL);
     counter = count_if(x, n, k);
     gettimeofday(&tv2, NULL);
     printf("if condition:         %.6lf (%ld)\n",
             tv2.tv_sec - tv1.tv_sec + 1.0e-6*(tv2.tv_usec - tv1.tv_usec),
             counter);
     gettimeofday(&tv1, NULL);
+    free(x);
+    x = init_cont(n, fraction);
     counter = count_cond_expr(x, n, k);
     gettimeofday(&tv2, NULL);
     printf("condition expression: %.6lf (%ld)\n",