Added the JUCE DSP module

modules/juce_dsp/maths/juce_Polynomial.h

@@ -0,0 +1,162 @@
+/*
+  ==============================================================================
+
+   This file is part of the JUCE library.
+   Copyright (c) 2017 - ROLI Ltd.
+
+   JUCE is an open source library subject to commercial or open-source
+   licensing.
+
+   By using JUCE, you agree to the terms of both the JUCE 5 End-User License
+   Agreement and JUCE 5 Privacy Policy (both updated and effective as of the
+   27th April 2017).
+
+   End User License Agreement: www.juce.com/juce-5-licence
+   Privacy Policy: www.juce.com/juce-5-privacy-policy
+
+   Or: You may also use this code under the terms of the GPL v3 (see
+   www.gnu.org/licenses).
+
+   JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
+   EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
+   DISCLAIMED.
+
+  ==============================================================================
+*/
+
+
+/**
+    A class representing a polynomial
+*/
+template <typename FloatingType>
+class Polynomial
+{
+public:
+    //==============================================================================
+    /** Creates a new polynomial which will always evaluate to zero. */
+    Polynomial()
+    {
+        coeffs.add (0);
+    }
+
+    /** Creates a new polynomial with given coefficients.
+
+        @param numCoefficients The number of coefficients stored in coefficients.
+                               This is also the order of the returned polynomial.
+        @param coefficients    The coefficients which will be used by the newly
+                               created polynomial. The Polynomial class will keep
+                               a private copy of the coefficients.
+    */
+    Polynomial (const FloatingType* coefficients, int numCoefficients)
+        : coeffs (coefficients, numCoefficients)
+    {
+        jassert (! coeffs.isEmpty());
+    }
+
+    /** Creates a copy of another polynomial. */
+    Polynomial (const Polynomial&) = default;
+
+    /** Creates a copy of another polynomial. */
+    Polynomial (Polynomial&&) = default;
+
+    /** Creates a copy of another polynomial. */
+    Polynomial& operator= (const Polynomial&) = default;
+
+    /** Creates a copy of another polynomial. */
+    Polynomial& operator= (Polynomial&&) = default;
+
+   #if JUCE_COMPILER_SUPPORTS_INITIALIZER_LISTS || defined(DOXYGEN)
+    /** Creates a new polynomial with coefficients by a C++11 initializer list.
+        This function can be used in the following way:
+        Polynomial<float> p ({0.5f, -0.3f, 0.2f});
+    */
+    template <typename TypeToCreateFrom>
+    Polynomial (const std::initializer_list<TypeToCreateFrom>& items)  : coeffs (items)
+    {
+        jassert (! coeffs.isEmpty());
+    }
+   #endif
+
+    //==============================================================================
+    /** Returns a single coefficient of the receiver for reading */
+    FloatingType operator[] (int index) const noexcept              { return coeffs.getUnchecked (index); }
+
+    /** Returns a single coefficient of the receiver for modifying. */
+    FloatingType& operator[] (int index) noexcept                   { return coeffs.getReference (index); }
+
+    /** Evaluates the value of the polynomial at a single point x. */
+    FloatingType operator() (FloatingType x) const noexcept
+    {
+        // Horner's method
+        FloatingType y = 0;
+
+        for (int i = coeffs.size(); --i >= 0;)
+            y = (x * y) + coeffs.getUnchecked(i);
+
+        return y;
+    }
+
+    /** Returns the order of the polynomial. */
+    int getOrder() noexcept
+    {
+        return coeffs.size() - 1;
+    }
+
+    //==============================================================================
+    /** Returns the polynomial with all its coefficients multiplied with a gain factor */
+    Polynomial<FloatingType> withGain (double gain) const
+    {
+        auto result = *this;
+
+        for (auto& c : result.coeffs)
+            c *= gain;
+
+        return result;
+    }
+
+    /** Returns the sum of this polynomial with another */
+    Polynomial<FloatingType> getSumWith (const Polynomial<FloatingType>& other) const
+    {
+        if (coeffs.size() < other.coeffs.size())
+            return other.getSumWith (*this);
+
+        auto result = *this;
+
+        for (int i = 0; i < other.coeffs.size(); ++i)
+            result[i] += other[i];
+
+        return result;
+    }
+
+    /** computes the product of two polynomials and return the result */
+    Polynomial<FloatingType> getProductWith (const Polynomial<FloatingType>& other) const
+    {
+        Polynomial<FloatingType> result;
+        result.coeffs.clearQuick();
+
+        auto N1 = coeffs.size();
+        auto N2 = other.coeffs.size();
+        auto Nmax = jmax (N1, N2);
+
+        auto N = N1 + N2 - 1;
+
+        for (int i = 0; i < N; ++i)
+        {
+            FloatingType value = {};
+
+            for (int j = 0; j < Nmax; ++j)
+                if (j >= 0 && j < N1 && i - j >= 0 && i - j < N2)
+                    value = value + (*this)[j] * other[i - j];
+
+            result.coeffs.add (value);
+        }
+
+        return result;
+    }
+
+private:
+    //==============================================================================
+    Array<FloatingType> coeffs;
+
+    JUCE_LEAK_DETECTOR (Polynomial)
+};