73 lines
1.3 KiB
C
73 lines
1.3 KiB
C
#include "solve.h"
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#include <math.h>
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#include <float.h>
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#include <stdbool.h>
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#include <stdint.h>
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#include <string.h>
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int t5_solve (
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double (*f) (double),
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double a, double b,
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double eps, int m, double *x
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) {
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int it;
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double c = (a + b) * 0.5;
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double y_a = f(a);
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double y_c = f(c);
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double y_b = f(b);
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if (is_null(y_a))
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return 1;
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else if (is_null(y_b))
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return 1;
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else if (is_null(y_c))
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return 1;
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if (is_equal(a, b))
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return -1;
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else if (is_equal(a, c))
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return -1;
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else if (is_equal(b, c))
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return -1;
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for (it = 1; it < m+1; ++it)
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{
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double *temp_pnt = 0, *inner_max_pnt;
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const double angle = (c - a) / (y_c - y_a);
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const double x_new = a -
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angle * y_a +
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((((b - c) / (y_b - y_c)) - angle) / (y_b - y_a)) * y_a * y_c;
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const double y_new = f(x_new);
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if (is_eps(y_new, eps))
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{
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*x = x_new;
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return it;
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}
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if (
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is_equal(x_new, a) ||
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is_equal(x_new, c) ||
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is_equal(x_new, b)
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)
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return -1;
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inner_max_pnt = fp_abs_max(&c, &b, &y_c, &y_b, &temp_pnt);
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*fp_abs_max(&a, inner_max_pnt, &y_a, temp_pnt, &temp_pnt) = x_new;
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if (fabs(y_new) - fabs(*temp_pnt) > DBL_EPSILON)
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return -4;
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*temp_pnt = y_new;
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}
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if (it > m)
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return -2;
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else
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{
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double temp = 0, *temp_x_pnt = fpmax(&c, &b, -y_c, -y_b, &temp);
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*x = *fpmax(&a, temp_x_pnt, -y_a, temp, &temp);
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return it;
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}
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}
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