You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: predictor.m
    path of file: ./repos/PlatEMO/PlatEMO/Algorithms/Multi-objective optimization/MOEA-D-PFE
    
    the code of the file until where you have to start completion: function [y,or1,or2,dmse] = predictor
    
function [r,dr] = corrgauss(theta,d)
%CORRGAUSS  Gaussian correlation function,

    [m,n] = size(d);  % number of differences and dimension of data
    if length(theta) == 1
        theta = repmat(theta,1,n);
    elseif length(theta) ~= n
        error('Length of theta must be 1 or %d',n)
    end