I try to find the coefficients of the polynomial using nonlinear regression analysis.

Question

haeyeon JI 2020-8-19

关闭： MATLAB Answer Bot 2021-8-20

The variables I will enter are magnitude M, distance R, and SA values corresponding to magnitude and distance.

for example,

M=[1 2 3]

R=[0 5 10 20 30 40 50 60 70]

SA is a Value corresponding to distance and magnitude : SA(M,R)

ex, SA(1,0) = 0.09

SA(1,5) = 0.06

SA(1,10) = 0.06

SA(1,20) = 0.03 ....

Estimated regression equation is

a*M+b*log(R+c)+d

I want to find the variables ' a,b and c ' through multiple non-linear regression.

The graph to be completed is as follows (values in the picture are examples, so irrelevant numbers)

此问题已关闭。

Answer 1

John D'Errico 2020-8-19

That function is not a polynomial.

Regardless, use one of many tools, thus lsqcurvefit or lsqnonlin from the optimization toolbox.

Use fit if you have the curvefitting toolbox.

Use fitnlm or nlinfit if you have the stats toolbox.