Add float_math.hpp for epsilon comparison; Test cleanup

4 files changed, 119 insertions, 2 deletions

diff --git a/include/jau/basic_algos.hpp b/include/jau/basic_algos.hpp
index b901789..1585781 100644
--- a/include/jau/basic_algos.hpp
+++ b/include/jau/basic_algos.hpp
@@ -27,7 +27,6 @@
 #define JAU_BASIC_ALGOS_HPP_
 
 #include <mutex>
-#include <cmath>
 
 namespace jau {
     /**
diff --git a/include/jau/float_math.hpp b/include/jau/float_math.hpp
new file mode 100644
index 0000000..4cac53c
--- /dev/null
+++ b/include/jau/float_math.hpp
@@ -0,0 +1,111 @@
+/*
+ * Author: Sven Gothel <[email protected]>
+ * Copyright (c) 2020 Gothel Software e.K.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#ifndef JAU_BASIC_FLOAT_MATH_HPP_
+#define JAU_BASIC_FLOAT_MATH_HPP_
+
+#include <cmath>
+#include <type_traits>
+#include <algorithm>
+
+namespace jau {
+    /**
+    // *************************************************
+    // *************************************************
+    // *************************************************
+     */
+
+    /**
+     * Returns true, if both integer point values differ less than the given delta.
+     * @tparam T an integral type
+     * @param a value to compare
+     * @param b value to compare
+     * @param delta the maximum difference both values may differ
+     */
+    template<class T>
+    bool in_range(const T& a, const T& b, const T& delta)
+    {
+        const T diff = std::fabs(a-b);
+        return diff <= delta ||
+               diff < std::numeric_limits<T>::min(); // subnormal limit
+    }
+
+    /**
+     * Calculates the smallest floating point value approximation
+     * the given type T can represent, the machine epsilon of T.
+     * @tparam T a non integer float type
+     * @return machine epsilon of T
+     */
+    template<class T>
+    typename std::enable_if<!std::numeric_limits<T>::is_integer, T>::type
+        machineEpsilon() {
+      const T one(1);
+      const T two(2);
+      T x = one, res;
+      do {
+          res = x;
+      } while (one + (x /= two) > one);
+      return res;
+    }
+
+    /**
+     * Returns true, if both floating point values are equal
+     * in the sense that their potential difference is less or equal <code>epsilon * ulp</code>.
+     * @tparam T a non integer float type
+     * @param a value to compare
+     * @param b value to compare
+     * @param ulp desired precision in ULPs (units in the last place), defaults to 1
+     * @param epsilon the machine epsilon of type T, defaults to <code>std::numeric_limits<T>::epsilon()</code>
+     */
+    template<class T>
+    typename std::enable_if<!std::numeric_limits<T>::is_integer, bool>::type
+        machine_equal(const T& a, const T& b, int ulp=1, const T& epsilon=std::numeric_limits<T>::epsilon())
+    {
+        const T diff = std::fabs(a-b);
+        return diff <= epsilon * ulp ||
+               diff < std::numeric_limits<T>::min(); // subnormal limit
+    }
+
+    /**
+     * Returns true, if both floating point values are equal
+     * in the sense that their potential difference is less or equal <code>epsilon * |a+b| * ulp</code>,
+     * where <code>|a+b|</code> scales epsilon to the magnitude of used values.
+     * @tparam T a non integer float type
+     * @param a value to compare
+     * @param b value to compare
+     * @param ulp desired precision in ULPs (units in the last place), defaults to 1
+     * @param epsilon the machine epsilon of type T, defaults to <code>std::numeric_limits<T>::epsilon()</code>
+     */
+    template<class T>
+    typename std::enable_if<!std::numeric_limits<T>::is_integer, bool>::type
+        almost_equal(const T& a, const T& b, int ulp=1, const T& epsilon=std::numeric_limits<T>::epsilon())
+    {
+        const T diff = std::fabs(a-b);
+        return diff <= epsilon * std::fabs(a+b) * ulp ||
+               diff < std::numeric_limits<T>::min(); // subnormal limit
+    }
+
+} // namespace jau
+
+#endif /* JAU_BASIC_FLOAT_MATH_HPP_ */
diff --git a/include/jau/int_math.hpp b/include/jau/int_math.hpp
index 92bacd7..cd37795 100644
--- a/include/jau/int_math.hpp
+++ b/include/jau/int_math.hpp
@@ -26,7 +26,6 @@
 #ifndef JAU_BASIC_INT_MATH_HPP_
 #define JAU_BASIC_INT_MATH_HPP_
 
-#include <mutex>
 #include <cmath>
 
 namespace jau {
diff --git a/include/jau/test/catch2_ext.hpp b/include/jau/test/catch2_ext.hpp
index 03a5d15..a7b9c6f 100644
--- a/include/jau/test/catch2_ext.hpp
+++ b/include/jau/test/catch2_ext.hpp
@@ -12,6 +12,7 @@
 #define CATCH2_EXT_H
 
 #include <catch2/catch_amalgamated.hpp>
+#include <jau/float_math.hpp>
 
 // namespace Catch {
 ///////////////////////////////////////////////////////////////////////////////
@@ -34,6 +35,13 @@
 
     #define REQUIRE_MSG(MSG, ... ) INTERNAL_CATCH_TEST_M( MSG, "REQUIRE: ", Catch::ResultDisposition::Normal, __VA_ARGS__  )
     #define INFO_STR( msg ) INTERNAL_CATCH_INFO( "INFO", static_cast<std::string>(msg) )
+
+    #define REQUIRE_EPSI(a,b)           INTERNAL_CATCH_TEST( "REQUIRE: ", Catch::ResultDisposition::Normal, jau::machine_equal(a, b))
+    #define REQUIRE_EPSI_MSG(m,a,b)     INTERNAL_CATCH_TEST_M( m, "REQUIRE: ", Catch::ResultDisposition::Normal, jau::machine_equal(a, b))
+
+    #define REQUIRE_DIFF(a,b,d)         INTERNAL_CATCH_TEST( "REQUIRE: ", Catch::ResultDisposition::Normal, jau::machine_equal(a, b, 1, d))
+    #define REQUIRE_DIFF_MSG(m,a,b,d)   INTERNAL_CATCH_TEST_M( m, "REQUIRE: ", Catch::ResultDisposition::Normal, jau::machine_equal(a, b, 1, d))
+
 // }
 
 #endif // CATCH2_EXT_H