47 lines
629 B
C
47 lines
629 B
C
#include "solve.h"
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#include <math.h>
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#include <float.h>
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#define MAX_ITER 30
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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, double *res
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) {
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int it;
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double n = 1;
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double h = (b - a);
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double integ_n = (f(a) + f(b)) * h*0.5;
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for (it = 1; it <= MAX_ITER; ++it)
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{
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double x = a + h*0.5;
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double integ_2n = 0;
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for (int i = 0; i < n; i++)
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{
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integ_2n += f(x);
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x += h;
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}
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h *= 0.5;
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integ_2n = integ_2n * h + integ_n * 0.5;
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if (fabs(integ_2n - integ_n) < eps)
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break;
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integ_n = integ_2n;
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n *= 2;
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}
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if (it > MAX_ITER)
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return -1;
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*res = integ_n;
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return n;
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}
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