#include"interpolation.h"
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#include "math.h"
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#include <stdlib.h>
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void interpolation(const float *x, const float *y, int Num, float x0, float*y0)
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{
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int i, index;
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float k;
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if (x0 <= x[0])
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{
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k = y[0];
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}
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else if (x0 >= x[Num - 1])
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{
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k = y[Num - 1];
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}
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else
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{
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for (i = 0; i < Num; i++)
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{
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if (x0 < x[i])
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break;
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}
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index = i - 1;
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if ((float)x[index + 1] - (float)x[index] < 0.001)
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k = (float)y[index];
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else
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k = ((float)x0 - (float)x[index]) / ((float)x[index + 1] - (float)x[index])
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* ((float)y[index + 1] - (float)y[index])
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+ (float)y[index];
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}
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*y0 = k;
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}
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void interpolation(const float *x, const unsigned short *y, int Num, float x0, unsigned short *y0)
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{
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int i, index;
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float k;
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if (x0 <= x[0])
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{
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k = y[0];
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}
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else if (x0 >= x[Num - 1])
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{
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k = y[Num - 1];
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}
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else
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{
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for (i = 0; i < Num; i++)
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{
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if (x0 < x[i])
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break;
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}
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index = i - 1;
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if ((float)x[index + 1] - (float)x[index] < 0.001)
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k = (float)y[index];
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else
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k = ((float)x0 - (float)x[index]) / ((float)x[index + 1] - (float)x[index])
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* ((float)y[index + 1] - (float)y[index])
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+ (float)y[index];
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}
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*y0 = (unsigned short)(k+0.5);
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}
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int interpolation(unsigned char *x, bool *y, int xNum, unsigned char x0, bool *y0)
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{
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int i, index;
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bool k;
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if (x0 <= x[0] || x0 <= x[1])
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{
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k = y[0];
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index = 0;
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}
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else if (x0 >= x[xNum - 1])
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{
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k = y[xNum - 2];
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index = xNum - 2;
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}
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else {
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for (i = 0; i < xNum; i++)
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{
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if (x0 < x[i])
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break;
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}
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index = i - 1;
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if (abs(x[index + 1] - x0) > abs(x0 - x[index])) {
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k = y[index - 1];
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}
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else {
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k = y[index];
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}
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}
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*y0 = k;
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return(index);
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}
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