svdvar.cpp

《VC++ 常用数值算法》代码

void svdvar(double v[], int ma, int np, double w[], double cvm[], int ncvm)
{
	double wti[21];
	int i,j;
	for (i = 1; i<=ma; i++)
	{
		wti[i] = 0.0;
		if (w[i] != 0.0)
		{
			wti[i] = 1.0 / (w[i] * w[i]);
		}
	}
	for (i = 1; i<=ma; i++)
	{
		for (j = 1; j<=i; j++)
		{
			double sum1 = 0.0;
			for (int k = 1; k<=ma; k++)
			{
				sum1 = sum1 + v[(i-1)*np+k] * v[(j-1)*np+k] * wti[k];
			}
			cvm[(i-1)*ma+j] = sum1;
			cvm[(j-1)*ma+i] = sum1;
		}
	}
}