33 lines
524 B
C
33 lines
524 B
C
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#include <math.h>
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#define FUNC(x) ((*funk)(-log(x))/(x))
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float midexp(float (*funk)(float), float aa, float bb, int n)
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{
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float x,tnm,sum,del,ddel,a,b;
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static float s;
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int it,j;
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b=exp(-aa);
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a=0.0;
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if (n == 1) {
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return (s=(b-a)*FUNC(0.5*(a+b)));
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} else {
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for(it=1,j=1;j<n-1;j++) it *= 3;
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tnm=it;
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del=(b-a)/(3.0*tnm);
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ddel=del+del;
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x=a+0.5*del;
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sum=0.0;
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for (j=1;j<=it;j++) {
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sum += FUNC(x);
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x += ddel;
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sum += FUNC(x);
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x += del;
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}
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s=(s+(b-a)*sum/tnm)/3.0;
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return s;
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}
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}
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#undef FUNC
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