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电桥特性曲线:
Java实现最小二乘法线性拟合及计算灵敏度、非线性误差的代码:
/*** @Author: Yeman* @Date: 2021-10-29-23:03* @Description:*/
public class LeastSquares {public static void matching(double[] x, double[] y, double[] input) {double k = getK(x, y);double b = getB(x, y);System.out.println("线性回归系数k值:\t" + k + "\n" + "线性回归系数b值:\t" + b);double maxy = 0; //用来记录最大偏差//寻找最大偏差for (int i = 0; i < input.length; i++) {if (Math.abs(k * input[i] + b - y[i]) > maxy){maxy = Math.abs(k * input[i] + b - y[i]);}}System.out.println("最大偏差为:" + maxy);//求灵敏度double s = 0;double sum = 0;for (int i = 1; i < y.length; i++) {sum += y[i] - y[i-1];}s = sum / (y.length - 1) / 20;System.out.println("灵敏度为:" + s);//求线性误差System.out.println("非线性误差为:" + maxy/y[10]);}/** 返回x的系数k 公式:k = ( n sum( xy ) - sum( x ) sum( y ) ) / ( n sum( x^2 ) - sum(x) ^ 2 )*/public static double getK(double[] x, double[] y) {int n = x.length;return (double) ((n * pSum(x, y) - sum(x) * sum(y)) / (n * sqSum(x) - Math.pow(sum(x), 2)));}/** 返回常量系数系数b 公式:b = sum( y ) / n - k * sum( x ) / n*/public static double getB(double[] x, double[] y) {int n = x.length;double k = getK(x, y);return sum(y) / n - k * sum(x) / n;}/** 求和*/private static double sum(double[] ds) {double s = 0;for (double d : ds){s = s + d;}return s;}/** 求平方和*/private static double sqSum(double[] ds) {double s = 0;for (double d : ds) {s = (double) (s + Math.pow(d, 2));}return s;}/** 返回对应项相乘后的和*/private static double pSum(double[] x, double[] y) {double s = 0;for (int i = 0; i < x.length; i++) {s = s + x[i] * y[i];}return s;}public static void main(String[] args) {double[] x = {0,20,40,60,80,100,120,140,160,180,200};double[] y1 = {0,4.1,8.1,12.2,17.1,21.7,25.8,29.9,34.1,37.8,43.3};double[] y2 = {0,7.5,15.1,22.9,30.7,38.6,46.3,54.2,62.0,69.9,77.8};double[] y3 = {0,15.0,31.3,47.0,62.6,78.3,93.8,109.6,125.5,141.2,157.3};double[] inputs = x;System.out.println("===单臂电桥:");matching(x, y1,inputs);System.out.println("======半桥:");matching(x, y2,inputs);System.out.println("======全桥:");matching(x, y3,inputs);}
}