Minor cleanup, doc++, updated changelog & credits.

doc/changelog.dox

@@ -64,6 +64,7 @@ See also:
 @subsubsection changelog-latest-new-math Math library
 
 -   Added @ref Math::fmod() (see [mosra/magnum#454](https://github.com/mosra/magnum/pull/454))
+-   Added @ref Math::binomialCoefficient() (see [mosra/magnum#461](https://github.com/mosra/magnum/pull/461))
 
 @subsection changelog-latest-changes Changes and improvements
 
@@ -139,7 +140,7 @@ See also:
     @ref Corrade::Containers::ArrayView are now removed. This should have a
     significant positive effect on compile times of code using the @ref GL,
     @ref Audio, @ref Trade and @ref Text librariess
--   @ref SceneGraph::Object:addChild() no longer requires the type constructor
+-   @ref SceneGraph::Object::addChild() no longer requires the type constructor
     to have the last parameter a parent object object pointer, as that was
     quite limiting. Instead it's calling @ref SceneGraph::Object::setParent()
     afterwards. This can cause compilation breakages in case the type

doc/credits.dox

@@ -143,6 +143,7 @@ Are the below lists missing your name or something's wrong?
     bootstrap project
 -   **Jan Dupal** ([\@JanDupal](https://github.com/JanDupal)) --- Homebrew
     package for `magnum-bindings`
+-   **[\@Janos95](https://github.com/Janos95)** -- @ref Math additions
 -   **Jonathan Hale** ([\@Squareys](https://github.com/Squareys)) ---
     @ref Audio and @ref Trade library enhancements,
     @ref Platform::GlfwApplication and @ref Platform::EmscriptenApplication

src/Magnum/Math/Functions.cpp

@@ -3,6 +3,7 @@
 
     Copyright © 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019,
                 2020 Vladimír Vondruš <mosra@centrum.cz>
+    Copyright © 2020 janos <janos.meny@googlemail.com>
 
     Permission is hereby granted, free of charge, to any person obtaining a
     copy of this software and associated documentation files (the "Software"),
@@ -43,19 +44,23 @@ UnsignedInt log2(UnsignedInt number) {
     return log;
 }
 
+UnsignedLong binomialCoefficient(const UnsignedInt n, UnsignedInt k) {
+    if(k > n) return 0;
 
-UnsignedLong binomialCoefficient(UnsignedInt n, UnsignedInt k) {
+    /* k and n - k gives the same value, optimize the calculation to do fewer
-    if (k > n) return 0;
+       steps */
-    if (k * 2 > n)
+    if(k*2 > n) k = n - k;
-        k = n-k;
+
-    if (k == 0) return 1;
+    if(k == 0) return 1;
 
     UnsignedLong result = n;
-    for(UnsignedInt i = 2; i <= k; ++i ) {
+    for(UnsignedInt i = 2; i <= k; ++i) {
-        CORRADE_ASSERT(result < ~UnsignedLong{} / (n-i+1), "Math::binomialCoefficient(): overflow for (" << Corrade::Utility::Debug::nospace << n << "choose" << k << Corrade::Utility::Debug::nospace << ")", 0ul);
+        CORRADE_ASSERT(result < ~UnsignedLong{} / (n-i+1), "Math::binomialCoefficient(): overflow for (" << Corrade::Utility::Debug::nospace << n << "choose" << k << Corrade::Utility::Debug::nospace << ")", {});
-        result *= (n-i+1);
+
+        result *= n - i + 1;
         result /= i;
     }
+
     return result;
 }
 

src/Magnum/Math/Functions.h

@@ -7,6 +7,7 @@
                 2020 Vladimír Vondruš <mosra@centrum.cz>
     Copyright © 2020 Nghia Truong <nghiatruong.vn@gmail.com>
     Copyright © 2020 Pablo Escobar <mail@rvrs.in>
+    Copyright © 2020 janos <janos.meny@googlemail.com>
 
     Permission is hereby granted, free of charge, to any person obtaining a
     copy of this software and associated documentation files (the "Software"),
@@ -410,14 +411,16 @@ template<std::size_t size, class T> inline Vector<size, T> ceil(const Vector<siz
     return out;
 }
 
-
 /**
-@brief [Binomial Coefficient](https://en.wikipedia.org/wiki/Binomial_coefficient)
+@brief [Binomial coefficient](https://en.wikipedia.org/wiki/Binomial_coefficient).
+@m_since_latest
 
-Returns the number of combinations of @f$ n @f$ things taken @f$ k @f$ at a time.
+Returns the number of combinations of @f$ n @f$ things taken @f$ k @f$ at a
-The number of ways to do this is given by
+time, with @f$ n \ge k \ge 0 @f$: @f[
-@f[
+    \begin{pmatrix} n \\ k \end{pmatrix} =
-    \begin{pmatrix} n \\ k \end{pmatrix} = \frac{n! \cdot (n-k)!}{k!} = \frac{n \cdot (n-1) \cdots (n - k + 1)}{k \cdots 1}.
+        \frac{n! (n - k)!}{k!} =
+        \frac{n (n - 1) (n - 2) ~ \cdots ~ (n - (k - 1))}{k (k - 1) ~ \cdots ~ 1} =
+        \prod_{i=1}^k \frac{n + 1 - i}{i}
 @f]
 */
 UnsignedLong MAGNUM_EXPORT binomialCoefficient(UnsignedInt n, UnsignedInt k);

src/Magnum/Math/Test/FunctionsTest.cpp

@@ -3,6 +3,7 @@
 
     Copyright © 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019,
                 2020 Vladimír Vondruš <mosra@centrum.cz>
+    Copyright © 2020 janos <janos.meny@googlemail.com>
 
     Permission is hereby granted, free of charge, to any person obtaining a
     copy of this software and associated documentation files (the "Software"),