23 lines
438 B
C++
23 lines
438 B
C++
#include "nr.h"
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void NR::splint(Vec_I_DP &xa, Vec_I_DP &ya, Vec_I_DP &y2a, const DP x, DP &y)
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{
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int k;
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DP h,b,a;
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int n=xa.size();
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int klo=0;
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int khi=n-1;
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while (khi-klo > 1) {
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k=(khi+klo) >> 1;
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if (xa[k] > x) khi=k;
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else klo=k;
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}
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h=xa[khi]-xa[klo];
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if (h == 0.0) nrerror("Bad xa input to routine splint");
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a=(xa[khi]-x)/h;
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b=(x-xa[klo])/h;
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y=a*ya[klo]+b*ya[khi]+((a*a*a-a)*y2a[klo]
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+(b*b*b-b)*y2a[khi])*(h*h)/6.0;
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}
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