Adding upstream version 1.3.upstream/1.3upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 147 insertions, 0 deletions

diff --git a/include/2geom/choose.h b/include/2geom/choose.h
new file mode 100644
index 0000000..106d04f
--- /dev/null
+++ b/include/2geom/choose.h
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+/**
+ * \file
+ * \brief Calculation of binomial cefficients
+ *//*
+ * Copyright 2006 Nathan Hurst <njh@mail.csse.monash.edu.au>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it either under the terms of the GNU Lesser General Public
+ * License version 2.1 as published by the Free Software Foundation
+ * (the "LGPL") or, at your option, under the terms of the Mozilla
+ * Public License Version 1.1 (the "MPL"). If you do not alter this
+ * notice, a recipient may use your version of this file under either
+ * the MPL or the LGPL.
+ *
+ * You should have received a copy of the LGPL along with this library
+ * in the file COPYING-LGPL-2.1; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ * You should have received a copy of the MPL along with this library
+ * in the file COPYING-MPL-1.1
+ *
+ * The contents of this file are subject to the Mozilla Public License
+ * Version 1.1 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
+ * OF ANY KIND, either express or implied. See the LGPL or the MPL for
+ * the specific language governing rights and limitations.
+ *
+ */
+
+#ifndef LIB2GEOM_SEEN_CHOOSE_H
+#define LIB2GEOM_SEEN_CHOOSE_H
+
+#include <vector>
+
+namespace Geom {
+
+/**
+ * @brief Given a multiple of binomial(n, k), modify it to the same multiple of binomial(n + 1, k).
+ */
+template <typename T>
+constexpr void binomial_increment_n(T &b, int n, int k)
+{
+    b = b * (n + 1) / (n + 1 - k);
+}
+
+/**
+ * @brief Given a multiple of binomial(n, k), modify it to the same multiple of binomial(n - 1, k).
+ */
+template <typename T>
+constexpr void binomial_decrement_n(T &b, int n, int k)
+{
+    b = b * (n - k) / n;
+}
+
+/**
+ * @brief Given a multiple of binomial(n, k), modify it to the same multiple of binomial(n, k + 1).
+ */
+template <typename T>
+constexpr void binomial_increment_k(T &b, int n, int k)
+{
+    b = b * (n - k) / (k + 1);
+}
+
+/**
+ * @brief Given a multiple of binomial(n, k), modify it to the same multiple of binomial(n, k - 1).
+ */
+template <typename T>
+constexpr void binomial_decrement_k(T &b, int n, int k)
+{
+    b = b * k / (n + 1 - k);
+}
+
+/**
+ * @brief Calculate the (n, k)th binomial coefficient.
+ */
+template <typename T>
+constexpr T choose(unsigned n, unsigned k)
+{
+    if (k > n) {
+        return 0;
+    }
+    T b = 1;
+    int max = std::min(k, n - k);
+    for (int i = 0; i < max; i++) {
+        binomial_increment_k(b, n, i);
+    }
+    return b;
+}
+
+/**
+ * @brief Class for calculating and accessing a row of Pascal's triangle.
+ */
+template <typename ValueType>
+class BinomialCoefficient
+{
+public:
+    using value_type = ValueType;
+    using container_type = std::vector<value_type>;
+
+    BinomialCoefficient(unsigned int _n)
+        : n(_n)
+    {
+        coefficients.reserve(n / 2 + 1);
+        coefficients.emplace_back(1);
+        value_type b = 1;
+        for (int i = 0; i < n / 2; i++) {
+            binomial_increment_k(b, n, i);
+            coefficients.emplace_back(b);
+        }
+    }
+
+    unsigned int size() const
+    {
+        return degree() + 1;
+    }
+
+    unsigned int degree() const
+    {
+        return n;
+    }
+
+    value_type operator[](unsigned int k) const
+    {
+        return coefficients[std::min(k, n - k)];
+    }
+
+private:
+    int const n;
+    container_type coefficients;
+};
+
+} // namespace Geom
+
+#endif // LIB2GEOM_SEEN_CHOOSE_H
+
+/*
+  Local Variables:
+  mode:c++
+  c-file-style:"stroustrup"
+  c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
+  indent-tabs-mode:nil
+  fill-column:99
+  End:
+*/
+// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:fileencoding=utf-8:textwidth=99 :