Math: added pow(), log() and exp().

Just wrappers around std::pow(), std::log() and std::exp() to have the
complete toolbox consistent.

src/Magnum/Math/Functions.h

@@ -66,6 +66,14 @@ template<UnsignedInt exponent, class T> constexpr T pow(T base) {
     return Implementation::Pow<exponent>::pow(base);
 }
 
+/**
+@brief Power
+
+Returns power of @p base to the @p exponent.
+@see @ref pow(T), @ref exp()
+*/
+template<class T> T pow(T base, T exponent) { return std::pow(base, exponent); }
+
 /**
 @brief Integral logarithm
 
@@ -82,6 +90,22 @@ Returns integral logarithm of given number with base `2`.
 */
 UnsignedInt MAGNUM_EXPORT log2(UnsignedInt number);
 
+/**
+@brief Natural logarithm
+
+Returns natural (base @f$ e @f$) logarithm of given number.
+@see @ref Constants::e(), @ref log(UnsignedInt, UnsignedInt), @ref log2()
+*/
+template<class T> T log(T number) { return std::log(number); }
+
+/**
+@brief Natural exponential
+
+Returns @f$ e^x @f$.
+@see @ref Constants::e(), @ref pow(T, T)
+*/
+template<class T> T exp(T exponent) { return std::exp(exponent); }
+
 /**
 @brief Integer division with remainder
 

src/Magnum/Math/Test/FunctionsTest.cpp

@@ -65,8 +65,11 @@ struct FunctionsTest: Corrade::TestSuite::Tester {
     void normalizeTypeDeduction();
 
     void powIntegral();
+    void pow();
     void logIntegral();
     void log2();
+    void log();
+    void exp();
     void div();
     void trigonometric();
     void trigonometricWithBase();
@@ -113,8 +116,11 @@ FunctionsTest::FunctionsTest() {
               &FunctionsTest::normalizeTypeDeduction,
 
               &FunctionsTest::powIntegral,
+              &FunctionsTest::pow,
               &FunctionsTest::logIntegral,
               &FunctionsTest::log2,
+              &FunctionsTest::log,
+              &FunctionsTest::exp,
               &FunctionsTest::div,
               &FunctionsTest::trigonometric,
               &FunctionsTest::trigonometricWithBase});
@@ -441,6 +447,10 @@ void FunctionsTest::powIntegral() {
     CORRADE_COMPARE(a, 125);
 }
 
+void FunctionsTest::pow() {
+    CORRADE_COMPARE(Math::pow(2.0f, 0.5f), 1.414213562f);
+}
+
 void FunctionsTest::logIntegral() {
     CORRADE_COMPARE(Math::log(2, 256), 8ul);
     CORRADE_COMPARE(Math::log(256, 2), 0ul);
@@ -450,6 +460,14 @@ void FunctionsTest::log2() {
     CORRADE_COMPARE(Math::log2(2153), 11);
 }
 
+void FunctionsTest::log() {
+    CORRADE_COMPARE(Math::log(2.0f), 0.693147f);
+}
+
+void FunctionsTest::exp() {
+    CORRADE_COMPARE(Math::exp(0.693147f), 2.0f);
+}
+
 void FunctionsTest::div() {
     Int quotient, remainder;
     std::tie(quotient, remainder) = Math::div(57, 6);