64 lines
908 B
C
64 lines
908 B
C
#include "solve.h"
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#include "status.h"
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#include <math.h>
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#include <float.h>
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int t8_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 = 0;
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status ret = SUCCESS;
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double c = DBL_MAX, y, y_a = f(a), y_b = f(b);
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if (fabs(y_a) - eps < DBL_EPSILON)
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{
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*x = a;
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return SUCCESS;
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} if (fabs(y_b) - eps < DBL_EPSILON)
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{
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*x = b;
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return SUCCESS;
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} if (fabs(fabs(y_b) - fabs(y_a)) < DBL_EPSILON)
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{
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*x = a;
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return EQUAL;
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}
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for (it = 0; it < m; ++it)
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{
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double h = (b - a) * 0.1;
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c = a + h;
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y = f(c);
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if (fabs(y) - eps < DBL_EPSILON)
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{
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ret = SUCCESS;
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break;
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} else if (fabs(y_a) - fabs(y_b) > DBL_EPSILON)
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{
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a = c;
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y_a = y;
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} else if (fabs(y_b) - fabs(y_a) > DBL_EPSILON)
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{
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b = c;
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y_b = y;
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} else
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{
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ret = EQUAL;
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break;
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}
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}
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if (it >= m)
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ret = RUN_TIME;
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*x = c;
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*m_it = it;
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return ret;
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}
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