Basis function custom problem in fitrgp()

I used hfcn = @(x)[v1,x]; to custom my own basis function when I fit Gaussian Process Regression using fitrgp(x,y,'BasisFunction',hfcn,'Beta',beta0,'KernelFunction','ardsquaredexponential','Verbose',1, ... 'Optimizer','fminunc', .... However, I was returned with an error "Error using cat. Dimensions of matrices being concatenated are not consistent." I am pretty sure that my v1 is of dimension n by 1 and my x used in fitrgp() is of dimension n by 1 as well. Could you please let me know anything wrong?

Answer 1

[Hyunjung Lee]

What is the dimension of beta0? I would suggest that you check if beta0 is a 2 by 1 matrix since your basis is n by 2.