133 lines
3.9 KiB
Java
133 lines
3.9 KiB
Java
package com.gunshi.project.hsz.model;
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import lombok.Data;
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import java.math.BigDecimal;
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import java.math.RoundingMode;
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import java.util.List;
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/**
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* 线性回归方程实体类
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*/
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@Data
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public class RegressionEquation {
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/**
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* 方程阶数
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*/
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private int order;
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/**
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* 方程系数（从常数项到最高次项）
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* 例如：对于二次方程 y = ax² + bx + c，coefficients = [c, b, a]
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*/
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private List<BigDecimal> coefficients;
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/**
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* 相关系数 R²
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*/
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private BigDecimal rSquared;
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/**
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* 数据点数
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*/
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private int dataCount;
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/**
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* 方程字符串表示
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*/
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private String equationString;
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public RegressionEquation(int order, List<BigDecimal> coefficients, BigDecimal rSquared, int dataCount) {
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this.order = order;
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this.coefficients = coefficients;
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this.rSquared = rSquared;
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this.dataCount = dataCount;
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this.equationString = generateEquationString();
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}
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/**
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* 生成方程字符串（使用数学符号）
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*/
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private String generateEquationString() {
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StringBuilder sb = new StringBuilder("y = ");
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for (int i = coefficients.size() - 1; i >= 0; i--) {
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BigDecimal coeff = coefficients.get(i);
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if (coeff.compareTo(BigDecimal.ZERO) == 0) {
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continue;
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}
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// 符号处理
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if (sb.length() > 4 && coeff.compareTo(BigDecimal.ZERO) > 0) {
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sb.append(" + ");
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} else if (sb.length() > 4 && coeff.compareTo(BigDecimal.ZERO) < 0) {
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sb.append(" - ");
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coeff = coeff.abs();
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}
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// 系数和变量 - 保留至少20位小数
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if (i == 0) {
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// 常数项 - 保留至少20位小数
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sb.append(coeff.setScale(20, RoundingMode.HALF_UP).toPlainString());
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} else {
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// 非常数项 - 保留至少20位小数
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if (coeff.compareTo(BigDecimal.ONE) != 0 && coeff.compareTo(BigDecimal.ONE.negate()) != 0) {
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sb.append(coeff.setScale(20, RoundingMode.HALF_UP).toPlainString());
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}
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sb.append("x");
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if (i > 1) {
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// 使用Unicode上标数字
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sb.append(getSuperscript(i));
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}
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}
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}
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return sb.toString();
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}
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/**
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* 获取数字的Unicode上标表示
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*/
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private String getSuperscript(int number) {
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String numStr = String.valueOf(number);
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StringBuilder superscript = new StringBuilder();
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for (char c : numStr.toCharArray()) {
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switch (c) {
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case '0': superscript.append('⁰'); break;
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case '1': superscript.append('¹'); break;
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case '2': superscript.append('²'); break;
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case '3': superscript.append('³'); break;
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case '4': superscript.append('⁴'); break;
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case '5': superscript.append('⁵'); break;
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case '6': superscript.append('⁶'); break;
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case '7': superscript.append('⁷'); break;
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case '8': superscript.append('⁸'); break;
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case '9': superscript.append('⁹'); break;
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default: superscript.append(c);
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}
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}
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return superscript.toString();
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}
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/**
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* 根据x值预测y值
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*/
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public BigDecimal predict(BigDecimal x) {
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BigDecimal result = BigDecimal.ZERO;
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BigDecimal xPower = BigDecimal.ONE;
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for (int i = 0; i < coefficients.size(); i++) {
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result = result.add(coefficients.get(i).multiply(xPower));
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xPower = xPower.multiply(x);
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}
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return result;
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}
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@Override
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public String toString() {
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return String.format("%s", equationString);
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}
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}
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