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: infExact.m
    path of file: ./repos/hctsa/Toolboxes/gpml/inf
    
    the code of the file until where you have to start completion: function [post nlZ dnlZ] = infExact(hyp, mean, cov, lik, x, y)

    
function [post nlZ dnlZ] = infExact(hyp, mean, cov, lik, x, y)

% Exact inference for a GP with Gaussian likelihood. Compute a parametrization
% of the posterior, the negative log marginal likelihood and its derivatives
% w.r.t. the hyperparameters. See also "help infMethods".
%
% Copyright (c) by Carl Edward Rasmussen and Hannes Nickisch, 2014-12-08.
%                                      File automatically generated using noweb.
%
% See also INFMETHODS.M.

if iscell(lik), likstr = lik{1}; else likstr = lik; end