二元线性回归

	template<class TYPE>
	BOOL LinearRegression(TYPE x[], TYPE y[], int n, TYPE &a, TYPE &b)
	{
		TYPE	xs, ys, xys, xxs;
		int		i;

		xs = 0;
		ys = 0;
		xys = 0;
		xxs = 0;
		for(i=0; i<n; i++)
		{
			xs += x[i];
			ys += y[i];
			xys += x[i]*y[i];
			xxs += x[i]*x[i];
		}

		a = (xs*ys/n-xys)/(xs*xs/n-xxs);
		b = (ys-a*xs)/n;
		return TRUE;
	};

	template<class TYPE>
	BOOL LinearReg2BC(TYPE x[][2], TYPE y[], int n, TYPE &b, TYPE &c)
	{
		TYPE		tx[64], ty[64], x0;
		int			i;

		for(i=0; i<n; i++)
		{
			x0 = x[i][0];
			tx[i] = x[i][1] / x0;
			ty[i] = y[i] / x0;
		}

		NMath::LinearRegression(tx, ty, n, c, b);
		return TRUE;
	}

	template<class TYPE>
	BOOL	Equation2XSub(TYPE x[][2], TYPE y[], TYPE tx[][2], TYPE ty[], int i, int k)
	{
		tx[i][0] = x[i][0] - x[k][0];
		tx[i][1] = x[i][1] - x[k][1];
		ty[i] = y[i] - y[k];
		return TRUE;
	}

	template<class TYPE>
	BOOL LinearReg2X(TYPE x[][2], TYPE y[], int n, TYPE &a, TYPE &b, TYPE &c, TYPE *pq = NULL)
	{
		TYPE		tx[64][2], ty[64];
		int			i;
		TYPE		x0s, x1s, ys, ry, ey, er, q;

		if(n < 3)
			return FALSE;

		x0s = 0;
		x1s = 0;
		ys = 0;
		for(i=0; i<n; i++)
		{
			x0s += x[i][0];
			x1s += x[i][1];
			ys += y[i];
		}

		for(i=1; i<n; i++)
			Equation2XSub(x, y, tx, ty, i-1, i);
		Equation2XSub(x, y, tx, ty, n-1, 0);

		LinearReg2BC(tx, ty, n, b, c);
		a = (ys - x0s*b - x1s*c)/n;

		if(pq)
		{
			ey = 0;
			er = 0;
			for(i=0; i<n; i++)
			{
				ey += y[i]*y[i];
				ry = a + b*x[i][0] + c*x[i][1];
				er += (ry - y[i])*(ry - y[i]);
			}

			q = (ey-er)/ey;
			*pq = q;
			return TRUE;
		}

		return TRUE;
	}