I want to do a nonlinear regression analysis with MATLAB.

I want to do a nonlinear regression analysis with MATLAB.

For example

M=1, 2, 3, 4

R=1, 2, 3, 4

And SA is the value related to M and R, that is, SA(M,R)

ex)

SA(1,1) = 5

=a*1+b*log(1+c)+d

SA(1,2)= 7

=a*1+b*log(2+c)+d

SA(1,3)=

10 =a*1+b+log(3+c)+d

SA(3,4)=

10 =a*3+b+log(4+c)+d

How can you calculate the constants (coefficients a,b,c,d) in the following formula?

SA(M,R)=a*M+b*log(R+c)+d

Answer 1

[Abdolkarim Mohammadi]

If you have up to 2 independent variables, you can use curve fitting app (cftool). If you have 3 or more independent variables, you should use lsqcurvefit().