Merge branch 'stclib:master' into modifiedHEADmodified

1 files changed, 42 insertions, 0 deletions

diff --git a/misc/examples/algorithms/random.c b/misc/examples/algorithms/random.c
new file mode 100644
index 00000000..e457d329
--- /dev/null
+++ b/misc/examples/algorithms/random.c
@@ -0,0 +1,42 @@
+#include <stdio.h>
+#include <time.h>
+#include <stc/crand.h>
+
+int main(void)
+{
+    const long long N = 10000000, range = 1000000;
+    const uint64_t seed = (uint64_t)time(NULL);
+    crand_t rng = crand_init(seed);
+    clock_t t;
+
+    printf("Compare speed of full and unbiased ranged random numbers...\n");
+    long long sum = 0;
+    t = clock();
+    c_forrange (N)  {
+        sum += (int32_t)crand_u64(&rng);
+    }
+    t = clock() - t;
+    printf("full range\t\t: %f secs, %lld, avg: %f\n",
+           (double)t/CLOCKS_PER_SEC, N, (double)(sum/N));
+
+    crand_uniform_t dist1 = crand_uniform_init(0, range);
+    rng = crand_init(seed);
+    sum = 0;
+    t = clock();
+    c_forrange (N)  {
+        sum += crand_uniform(&rng, &dist1); // unbiased
+    }
+    t = clock() - t;
+    printf("unbiased 0-%lld\t: %f secs, %lld, avg: %f\n",
+           range, (double)t/CLOCKS_PER_SEC, N, (double)(sum/N));
+
+    sum = 0;
+    rng = crand_init(seed);
+    t = clock();
+    c_forrange (N)  {
+        sum += (int32_t)crand_u64(&rng) % (range + 1); // biased
+    }
+    t = clock() - t;
+    printf("biased 0-%lld  \t: %f secs, %lld, avg: %f\n",
+           range, (double)t/CLOCKS_PER_SEC, N, (double)(sum/N));
+}