Add files via upload

Author: garyexplains

leibniz.c

@@ -0,0 +1,96 @@
+// Copyright (C) <2024>, Gary Sims
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are met:
+//
+// 1. Redistributions of source code must retain the above copyright notice, this
+//   list of conditions and the following disclaimer.
+// 2. Redistributions in binary form must reproduce the above copyright notice,
+//   this list of conditions and the following disclaimer in the documentation
+//   and/or other materials provided with the distribution.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+// ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+// ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+
+#include <gmp.h>
+#include <stdio.h>
+#include <pthread.h>
+#include <string.h>
+
+// Prereq: sudo apt install libgmp-dev
+// Compile: gcc -o leibniz leibniz.c -lgmp -pthread
+
+//#define ITERATIONS 1000000000
+#define ITERATIONS 100000000
+#define PERC 512
+/*
+ * Shock, horror: globals!
+ */
+mpf_t pi4_plus;
+mpf_t pi4_minus;
+
+void *do_pi_minus(void *arg) {
+	unsigned long int i;
+	mpf_t oneoveri;
+	mpf_init2 (oneoveri, PERC);
+
+	for(i=3;i<ITERATIONS;i=i+4) {
+		mpf_set_ui(oneoveri, 1);
+		mpf_div_ui(oneoveri, oneoveri, i);
+		mpf_sub(pi4_minus, pi4_minus, oneoveri);
+	}
+	gmp_printf("%.*Ff\n",80, pi4_minus);
+}
+
+void *do_pi_plus(void * arg) {
+	unsigned long int i;
+	mpf_t oneoveri;
+	mpf_init2 (oneoveri, PERC);
+
+	for(i=5;i<ITERATIONS;i=i+4) {
+		mpf_set_ui(oneoveri, 1);
+		mpf_div_ui(oneoveri, oneoveri, i);
+		mpf_add(pi4_plus, pi4_plus, oneoveri);
+	}
+	gmp_printf("%.*Ff\n",80, pi4_plus);
+}
+
+int main() {
+	unsigned long int i;
+	mpf_t pi;
+	pthread_t plus_tid;
+	pthread_t minus_tid;
+	int err;
+
+	mpf_init2 (pi, PERC);
+	mpf_init2 (pi4_plus, PERC);
+	mpf_init2 (pi4_minus, PERC);
+	mpf_set_ui(pi4_minus, 1);
+
+
+	err = pthread_create( &minus_tid, NULL, &do_pi_minus, NULL);
+        if (err != 0)
+        	printf("\nCan't create thread :[%s]", strerror(err));
+
+	err = pthread_create( &plus_tid, NULL, &do_pi_plus, NULL);
+        if (err != 0)
+        	printf("\nCan't create thread :[%s]", strerror(err));
+
+	pthread_join(minus_tid, NULL);
+	pthread_join(plus_tid, NULL);
+
+	mpf_add(pi, pi4_plus, pi4_minus);
+	mpf_mul_ui(pi, pi, 4);
+	gmp_printf("%.*Ff\n",80, pi);
+
+}