svbksb.cpp

C++数值算法原书代码

#include "nr.h"

void NR::svbksb(Mat_I_DP &u, Vec_I_DP &w, Mat_I_DP &v, Vec_I_DP &b, Vec_O_DP &x)
{
	int jj,j,i;
	DP s;

	int m=u.nrows();
	int n=u.ncols();
	Vec_DP tmp(n);
	for (j=0;j<n;j++) {
		s=0.0;
		if (w[j] != 0.0) {
			for (i=0;i<m;i++) s += u[i][j]*b[i];
			s /= w[j];
		}
		tmp[j]=s;
	}
	for (j=0;j<n;j++) {
		s=0.0;
		for (jj=0;jj<n;jj++) s += v[j][jj]*tmp[jj];
		x[j]=s;
	}
}