42 lines
793 B
C++
42 lines
793 B
C++
#include <cmath>
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#include <complex>
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#include "nr.h"
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using namespace std;
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void NR::zroots(Vec_I_CPLX_DP &a, Vec_O_CPLX_DP &roots, const bool &polish)
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{
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const DP EPS=1.0e-14;
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int i,its,j,jj;
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complex<DP> x,b,c;
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int m=a.size()-1;
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Vec_CPLX_DP ad(m+1);
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for (j=0;j<=m;j++) ad[j]=a[j];
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for (j=m-1;j>=0;j--) {
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x=0.0;
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Vec_CPLX_DP ad_v(j+2);
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for (jj=0;jj<j+2;jj++) ad_v[jj]=ad[jj];
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laguer(ad_v,x,its);
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if (fabs(imag(x)) <= 2.0*EPS*fabs(real(x)))
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x=complex<DP>(real(x),0.0);
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roots[j]=x;
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b=ad[j+1];
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for (jj=j;jj>=0;jj--) {
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c=ad[jj];
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ad[jj]=b;
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b=x*b+c;
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}
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}
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if (polish)
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for (j=0;j<m;j++)
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laguer(a,roots[j],its);
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for (j=1;j<m;j++) {
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x=roots[j];
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for (i=j-1;i>=0;i--) {
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if (real(roots[i]) <= real(x)) break;
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roots[i+1]=roots[i];
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}
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roots[i+1]=x;
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}
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}
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