AGM

example/agm_example.cpp

@@ -0,0 +1,21 @@
+//  (C) Copyright Nick Thompson 2020.
+//  Use, modification and distribution are subject to the
+//  Boost Software License, Version 1.0. (See accompanying file
+//  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+#include <iostream>
+#include <boost/math/tools/agm.hpp>
+#include <boost/math/constants/constants.hpp>
+#include <boost/multiprecision/float128.hpp>
+
+// This example computes the lemniscate constant to high precision using the agm:
+using boost::math::tools::agm;
+using boost::math::constants::pi;
+using boost::multiprecision::float128;
+
+int main() {
+    using Real = float128;
+    Real G = agm(sqrt(Real(2)), Real(1));
+    std::cout << std::setprecision(std::numeric_limits<Real>::max_digits10);
+    std::cout << " Gauss's lemniscate constant = " << pi<Real>()/G << "\n";
+    std::cout << "Expected lemniscate constant = " << "2.62205755429211981046483958989111941368275495143162316281682170380079058707041425023029553296142909344613\n";
+}