From c8a7b59dcc8a1d6cd7bf5f5bc6b76f26a97b34d6 Mon Sep 17 00:00:00 2001
From: Tyge Løvset <tylo@norceresearch.no>
Date: Mon, 29 Mar 2021 14:27:14 +0200
Subject: Another update of cbits.

---
 examples/cbits_prime.c | 39 ---------------------------------------
 examples/prime.c       | 27 ++++++++++++---------------
 2 files changed, 12 insertions(+), 54 deletions(-)
 delete mode 100644 examples/cbits_prime.c

(limited to 'examples')

diff --git a/examples/cbits_prime.c b/examples/cbits_prime.c
deleted file mode 100644
index e2e7877a..00000000
--- a/examples/cbits_prime.c
+++ /dev/null
@@ -1,39 +0,0 @@
-#include <stdio.h>
-#include <stc/cbits.h>
-
-static inline cbits sieveOfEratosthenes(size_t n)
-{
-    cbits primes = cbits_with_size(n + 1, true);
-    cbits_reset(&primes, 0);
-    cbits_reset(&primes, 1);
-
-    c_forrange (i, size_t, 2, n+1) {
-        // If primes[i] is not changed, then it is a prime
-        if (cbits_test(primes, i) && i*i <= n) {
-            c_forrange (j, size_t, i*i, n+1, i) {
-                cbits_reset(&primes, j);
-            }
-        }
-    }
-    return primes;
-}
-
-
-int main(void)
-{
-    int n = 100000000;
-    printf("computing prime numbers up to %u\n", n);
-
-    cbits primes = sieveOfEratosthenes(n);
-    puts("done");
-
-    size_t np = cbits_count(primes);
-    printf("number of primes: %zu\n", np);
-
-    printf("2 ");
-    c_forrange (i, int, 3, 1001, 2) {
-       if (cbits_test(primes, i)) printf("%d ", i);
-    }
-    puts("");
-    cbits_del(&primes);
-}
\ No newline at end of file
diff --git a/examples/prime.c b/examples/prime.c
index f11f1627..39418c49 100644
--- a/examples/prime.c
+++ b/examples/prime.c
@@ -5,40 +5,37 @@
 
 cbits sieveOfEratosthenes(size_t n)
 {
-    cbits bits = cbits_with_pattern(n, 0xAAAAAAAAAAAAAAAA);
-    size_t q = sqrt(n);
-    cbits_reset(&bits, 1);
-    cbits_set(&bits, 2);
+    cbits bits = cbits_with_size(n>>1, true);
+    size_t q = (size_t) sqrt(n);
 
-    for (size_t j, i = 3; i <= q; i += 2) {
-        for (j = i; j < n; j += 2) {
-            if (cbits_test(bits, j)) {
+    for (size_t i = 3; i <= q; i += 2) {
+        for (size_t j = i; j < n; j += 2) {
+            if (cbits_test(bits, j>>1)) {
                 i = j;
                 break;
             }
         }
-        for (j = i*i; j < n; j += i*2)
-            cbits_reset(&bits, j);
+        for (size_t j = i*i; j < n; j += i*2)
+            cbits_reset(&bits, j>>1);
     }
     return bits;
 }
 
-
 int main(void)
 {
     size_t n = 100000000;
-    printf("computing prime numbers up to %u\n", n);
+    printf("computing prime numbers up to %zu\n", n);
 
     clock_t t1 = clock();
     cbits primes = sieveOfEratosthenes(n + 1);
     size_t np = cbits_count(primes);
     clock_t t2 = clock();
 
-    printf("number of primes: %zu, time: %f\n", np, (t2 - t1)/(float)CLOCKS_PER_SEC);
+    printf("number of primes: %zu, time: %f\n", np, (t2 - t1) / (float)CLOCKS_PER_SEC);
 
-    for (size_t i=0; i<=1000; ++i)
-       if (cbits_test(primes, i)) printf("%d ", i);
+    printf(" 2"); for (size_t i = 3; i < 1000; i += 2)
+       if (cbits_test(primes, i>>1)) printf(" %zu", i);
     puts("");
 
     cbits_del(&primes);
-}
\ No newline at end of file
+}
-- 
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