48 lines
1.4 KiB
C++
Executable File
48 lines
1.4 KiB
C++
Executable File
/*==============================================================================
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Copyright 2018 by Roland Rabien, Devin Lane
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For more information visit www.rabiensoftware.com
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==============================================================================*/
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#pragma once
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/** Cubic spline interpolation is a simple way to obtain a smooth curve from a set of
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discrete points. It has both C1 (first derivative) and C2 (second derivative) continuity,
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enabling it to produce a continuous piecewise function given a set of data points.
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Add points in increasing x order */
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class Spline
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{
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public:
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Spline (const Array<juce::Point<double>>& points);
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double operator[] (double x) const;
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double interpolate (double x) const;
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class Element
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{
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public:
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Element (double x_ = 0) : x (x_) {}
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Element (double x_, double a_, double b_, double c_, double d_)
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: x (x_), a (a_), b (b_), c (c_), d (d_) {}
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double eval (double xx) const
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{
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double xix (xx - x);
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return a + b * xix + c * (xix * xix) + d * (xix * xix * xix);
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}
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bool operator< (const Element& e) const { return x < e.x; }
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bool operator< (const double xx) const { return x < xx; }
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double x = 0, a = 0, b = 0, c = 0, d = 0;
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};
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private:
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Array<Element> elements;
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JUCE_LEAK_DETECTOR (Spline)
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};
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