29 lines
540 B
C++
29 lines
540 B
C++
#include <cmath>
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#include "nr.h"
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using namespace std;
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DP NR::qromb(DP func(const DP), DP a, DP b)
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{
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const int JMAX=20, JMAXP=JMAX+1, K=5;
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const DP EPS=1.0e-10;
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DP ss,dss;
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Vec_DP s(JMAX),h(JMAXP),s_t(K),h_t(K);
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int i,j;
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h[0]=1.0;
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for (j=1;j<=JMAX;j++) {
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s[j-1]=trapzd(func,a,b,j);
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if (j >= K) {
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for (i=0;i<K;i++) {
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h_t[i]=h[j-K+i];
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s_t[i]=s[j-K+i];
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}
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polint(h_t,s_t,0.0,ss,dss);
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if (fabs(dss) <= EPS*fabs(ss)) return ss;
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}
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h[j]=0.25*h[j-1];
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}
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nrerror("Too many steps in routine qromb");
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return 0.0;
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}
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