saying that Index in position 2 exceeds array bounds (must not exceed 1) for line 7

data_2=data(:,1);
data_1=data(:,2);
data_=data(:,3);    
stuff=data(:,4);   
log= @(p,x) -(p(1)+p(2)*x(:,1)).*x(:,3).^p(3);
guess=[4 1]
log_model=fitnlm(data_2,data_,log,guess);
calc_log=feval(log_model,[data_2,data_1,data_]);

[Adam Danz]

Please share the entire error message. Is line 7 the fitnlm line (line 7 in the code you shared)?

What's the size of data?

[Adam Danz]

That's a completely different error than the one in the title of your question.

[Rena Berman]

(Answers Dev) Restored edit

[Star Strider]

Rena — Thank you!

Answer 1

[Star Strider]

There are two problems that I can see.

First, ‘data_2’ is a column vector, so it does not have a second column, and ‘x’ must br a (Nx3) matrix, not a vector, or better than that, a (Nx2) matrix of the appropriate data vectors, and change the reference to ‘x(:,2)’. That is throwing an error where you refer to ‘x(:,3)’ in your (inappropriately-named) ‘log’ function. (Please name it something such as ‘log_model’ that does not overshadow a MATLAB function!)

Second, you are estimating 3 parameters, so ‘guess’ must have a value for each one of them. Right now, it only has values for 2.

Otherwise, this call:

log_model=fitnlm(data_2,data_,log,guess);

appears to be correct.

I cannot run your code, so there could be more problems that only running it could detect.