31 lines
616 B
C++
31 lines
616 B
C++
#include <cmath>
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#include "nr.h"
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using namespace std;
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extern Vec_DP *xx_p,*yy_p,*sx_p,*sy_p,*ww_p;
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extern DP aa,offs;
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DP NR::chixy(const DP bang)
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{
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const DP BIG=1.0e30;
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int j;
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DP ans,avex=0.0,avey=0.0,sumw=0.0,b;
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Vec_DP &xx=*xx_p, &yy=*yy_p;
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Vec_DP &sx=*sx_p, &sy=*sy_p, &ww=*ww_p;
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int nn=xx.size();
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b=tan(bang);
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for (j=0;j<nn;j++) {
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ww[j] = SQR(b*sx[j])+SQR(sy[j]);
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sumw += (ww[j]=(ww[j] < 1.0/BIG ? BIG : 1.0/ww[j]));
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avex += ww[j]*xx[j];
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avey += ww[j]*yy[j];
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}
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avex /= sumw;
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avey /= sumw;
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aa=avey-b*avex;
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for (ans = -offs,j=0;j<nn;j++)
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ans += ww[j]*SQR(yy[j]-aa-b*xx[j]);
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return ans;
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}
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