26 lines
470 B
C
26 lines
470 B
C
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#include <math.h>
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#define FACTOR 1.6
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#define NTRY 50
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int zbrac(float (*func)(float), float *x1, float *x2)
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{
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void nrerror(char error_text[]);
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int j;
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float f1,f2;
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if (*x1 == *x2) nrerror("Bad initial range in zbrac");
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f1=(*func)(*x1);
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f2=(*func)(*x2);
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for (j=1;j<=NTRY;j++) {
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if (f1*f2 < 0.0) return 1;
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if (fabs(f1) < fabs(f2))
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f1=(*func)(*x1 += FACTOR*(*x1-*x2));
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else
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f2=(*func)(*x2 += FACTOR*(*x2-*x1));
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}
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return 0;
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}
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#undef FACTOR
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#undef NTRY
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