function [y] = zhou98(xx) %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % % ZHOU (1998) FUNCTION % % Authors: Sonja Surjanovic, Simon Fraser University % Derek Bingham, Simon Fraser University % Questions/Comments: Please email Derek Bingham at dbingham@stat.sfu.ca. % % Copyright 2013. Derek Bingham, Simon Fraser University. % % THERE IS NO WARRANTY, EXPRESS OR IMPLIED. WE DO NOT ASSUME ANY LIABILITY % FOR THE USE OF THIS SOFTWARE. If software is modified to produce % derivative works, such modified software should be clearly marked. % Additionally, this program is free software; you can redistribute it % and/or modify it under the terms of the GNU General Public License as % published by the Free Software Foundation; version 2.0 of the License. % Accordingly, this program is distributed in the hope that it will be % useful, but WITHOUT ANY WARRANTY; without even the implied warranty % of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU % General Public License for more details. % % For function details and reference information, see: % http://www.sfu.ca/~ssurjano/ % %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % % INPUT: % % xx = [x1, x2, ..., xd] % %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% d = length(xx); for ii = 1:d xxa(ii) = 10 * (xx(ii)-1/3); end for ii = 1:d xxb(ii) = 10 * (xx(ii)-2/3); end phi1 = (2*pi)^(-d/2) * exp(-0.5*(norm(xxa))^2); phi2 = (2*pi)^(-d/2) * exp(-0.5*(norm(xxb))^2); y = (10^d)/2 * (phi1 + phi2); end