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: covSEfact.m
    path of file: ./repos/hctsa/Toolboxes/gpml/cov
    
    the code of the file until where you have to start completion: function K = covSEfact(d, hyp, x, z, i)

% Factor analysis squared exponential covariance.
%
% This provides a GPML-compatible covariance function implementing the
% The covariance function is parameterized as:
%
%   k(x,z) = sf^2 * cosSEiso(x*L',z*L'),
%
% where x and z are the inputs and, L is a (dxD) embedding matrix, sf is the
% signal standard deviation.
%

    
function K = covSEfact(d, hyp, x, z, i)

% Factor analysis squared exponential covariance.
%
% This provides a GPML-compatible covariance function implementing the
% The covariance function is parameterized as:
%
%   k(x,z) = sf^2 * cosSEiso(x*L',z*L'),
%
% where x and z are the inputs and, L is a (dxD) embedding matrix, sf is the
% signal standard deviation.
%
% The hyperparameters are:
% hyp = [ hypL
%         log(sf) ],
%
% where sf is the signal standard deviation and hypL is the vectorized L matrix.
% The conversion between hypL and L is achieved by the following code:
%
% conversion L -> hypL
% if d==1, diagL = L(1); else diagL = diag(L); end