71 lines
1.4 KiB
C
71 lines
1.4 KiB
C
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/*==============================================================================
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Copyright 2020 by Roland Rabien
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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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/** Lagrange interpolation is a simple way to obtain a smooth curve from a set of
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discrete points.
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*/
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namespace Lagrange
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{
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template <class T>
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T interpolate (const Array<juce::Point<T>>& points, T x)
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{
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T res = 0;
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const int num = points.size();
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for (int i = 0; i < num; i++)
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{
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T term = points[i].y;
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for (int j = 0; j < num; j++)
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{
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if (i != j)
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{
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auto d = points[i].x - points[j].x;
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if (d != 0)
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term = term * (x - points[j].x ) / (d);
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else
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term = 0;
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}
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}
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res += term;
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}
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return res;
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}
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template <class T>
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T interpolate (T xArr[], T yArr[], int num, T x)
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{
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T res = 0;
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for (int i = 0; i < num; i++)
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{
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T term = yArr[i];
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for (int j = 0; j < num; j++)
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{
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if (i != j)
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{
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auto d = xArr[i] - xArr[j];
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if (d != 0)
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term = term * (x - xArr[j] ) / d;
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else
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term = 0;
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}
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}
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res += term;
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}
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return res;
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}
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}
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