/**
* 最小二乘法計算類
*
* @author Administrator
*
*/
public class LeastSquareMethod {
\x05private double[] x;
\x05private double[] y;
\x05private double[] weight;
\x05private int m;
\x05private double[] coefficient;
\x05public LeastSquareMethod(double[] x,double[] y,int m) {
\x05\x05if (x == null || y == null || x.length < 2 || x.length != y.length
\x05\x05\x05\x05|| m < 2)
\x05\x05\x05throw new IllegalArgumentException("無效的參數(shù)");
\x05\x05this.x = x;
\x05\x05this.y = y;
\x05\x05this.m = m;
\x05\x05weight = new double[x.length];
\x05\x05for (int i = 0; i < x.length; i++) {
\x05\x05\x05weight[i] = 1;
\x05\x05}
\x05}
\x05public LeastSquareMethod(double[] x,double[] y,double[] weight,int m) {
\x05\x05if (x == null || y == null || weight == null || x.length < 2
\x05\x05\x05\x05|| x.length != y.length || x.length != weight.length || m < 2)
\x05\x05\x05throw new IllegalArgumentException("無效的參數(shù)");
\x05\x05this.x = x;
\x05\x05this.y = y;
\x05\x05this.m = m;
\x05\x05this.weight = weight;
\x05}
\x05public double[] getCoefficient() {
\x05\x05if (coefficient == null)
\x05\x05\x05compute();
\x05\x05return coefficient;
\x05}
\x05public double fit(double v) {
\x05\x05if (coefficient == null)
\x05\x05\x05compute();
\x05\x05if (coefficient == null)
\x05\x05\x05return 0;
\x05\x05double sum = 0;
\x05\x05for (int i = 0; i < coefficient.length; i++) {
\x05\x05\x05sum += Math.pow(v,i) * coefficient[i];
\x05\x05}
\x05\x05return sum;
\x05}
\x05private void compute() {
\x05\x05if (x == null || y == null || x.length