www.pudn.com > matlab.rar > delta.m, change:1996-02-06,size:1471b

function[change] = delta(ct,mt,y,b) % The delta function is the non-uniform distributions used by the nonUniform % mutations. This function returns a change based on the current gen, the % max gen and the amount of possible deviation. % % function[change] = delta(ct,mt,y,b) % ct - current generation % mt - maximum generation % y - maximum amount of change, i.e. distance from parameter value to bounds % b - shape parameter % Binary and Real-Valued Simulation Evolution for Matlab % Copyright (C) 1996 C.R. Houck, J.A. Joines, M.G. Kay % % C.R. Houck, J.Joines, and M.Kay. A genetic algorithm for function % optimization: A Matlab implementation. ACM Transactions on Mathmatical % Software, Submitted 1996. % % 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; either version 1, or (at your option) % any later version. % % 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. A copy of the GNU % General Public License can be obtained from the % Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. r=ct/mt; if(r>1) r=.99; % disp(sprintf('max gen %d < current gen %d setting ratio = 1',mt,ct)); end change = y*(rand*(1-r))^b;