28 lines
636 B
C
28 lines
636 B
C
#include "util.h"
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#include <stdint.h>
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float interp(uint32_t n_points, const float* source_x, const float* source_y,
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float target_x) {
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uint32_t i;
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for (i = 0; i < n_points; i++) {
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if (source_x[i] > target_x) {
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break;
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}
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}
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if (i == 0) {
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// target_x is smaller than the smallest value in source_x
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i++;
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}
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if (i == n_points) {
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// target_y is larger than the largest value in source_x
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i--;
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}
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float x1 = source_x[i - 1];
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float x2 = source_x[i];
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float y1 = source_y[i - 1];
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float y2 = source_y[i];
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float slope = (y2 - y1) / (x2 - x1);
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return y1 + slope * (target_x - x1);
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}
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