希望虫友能给与帮助
采用多元非线性回归：
data.txt
168.7 202.9 145.9 12.1
142.0 206.4 152.9 15.8
181.9 205.8 144.2 10.7
119.7 206.8 156.2 20.9
243.9 203.9 130.6 5.0
170.1 205.8 141.9 17.2
167.3 200.1 138.7 16.3
269.2 203.2 132.0 9.7
254.1 205.4 128.9 10.6
325.2 208.8 123.4 6.7
83.9 210.0 153.4 17.1
26.7 206.4 176.6 92.9
-1.3 207.1 190.8 149.8
79.3 209.2 157.2 21.4
68.2 210.6 167.9 44.7
41.1 205.2 162.9 61.3
8.4 198.8 176.1 115.7
50.1 209.8 167.3 64.9
189.7 216.8 160.2 20.9
50.7 200.4 158.2 46.4
35.9 207.1 167.9 64.0
function main
clc
clear
data=load('data.txt');
y=data(:,1);
x=data(:,2:4);
beta=; % 回归系数的初值,任意取
yy=fun(beta,x);
=nlinfit(x,y,@fun,beta);
beta_out
mse
betaci=nlparci(beta_out,r,'Jacobian',J);
betaa=
=nlpredci(@fun,x,beta_out,r,'Jacobian',J);
alpha=0.05;
nlintool(x,y,'fun',beta,alpha)
r=corrcoef(y,yy) % 求相关系数r
plotregression(y,yy) % 并且画图r
regstats(y,yy)
function yy=fun(beta,x)
b1 = beta(1);
b2 = beta(2);
b3 = beta(3);
b4 = beta(4);
yy=b1*(x(:,1).^b2).*(x(:,2).^b3).*(x(:,3).^b4);
运行时显示??? Error: File: D:\新建文件夹\main.m Line: 9 Column: 1
The expression to the left of the equals sign is not a valid target for an assignment.
