[ci skip] Modular exponentiation, modular multiplicative inverse, extended Euclidean algorithm, discrete logarithm.

test/extended_euclidean_test.cpp

@@ -0,0 +1,41 @@
+/*
+ *  (C) Copyright Nick Thompson 2018.
+ *  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)
+ */
+#define BOOST_TEST_MODULE extended_euclidean_test
+#include <boost/test/included/unit_test.hpp>
+#include <boost/multiprecision/cpp_int.hpp>
+#include <boost/integer/common_factor.hpp>
+#include <boost/integer/extended_euclidean.hpp>
+
+using boost::multiprecision::int128_t;
+using boost::integer::extended_euclidean;
+using boost::integer::gcd;
+
+template<class Z>
+void test_extended_euclidean()
+{
+    Z max_arg = 500;
+    for (Z m = 1; m < max_arg; ++m)
+    {
+        for (Z n = 1; n < max_arg; ++n)
+        {
+            std::tuple<Z, Z, Z> u = extended_euclidean(m, n);
+            Z gcdmn = gcd(m, n);
+            Z x = std::get<1>(u);
+            Z y = std::get<2>(u);
+            BOOST_CHECK_EQUAL(std::get<0>(u), gcdmn);
+            BOOST_CHECK_EQUAL(m*x + n*y, gcdmn);
+        }
+    }
+}
+
+BOOST_AUTO_TEST_CASE(extended_euclidean_test)
+{
+    test_extended_euclidean<int>();
+    test_extended_euclidean<long>();
+    test_extended_euclidean<size_t>();
+    test_extended_euclidean<int128_t>();
+}