gusucode.com > 语音信号处理工具箱 - Voicebox源码程序 > Voicebox\logsum.m
function y=logsum(x,d) %LOGSUM logsum(x,d)=log(sum(exp(x),d)) % d gives dimension to sum along % Copyright (C) Mike Brookes 1998 % % Last modified Mon Oct 12 15:47:25 1998 % % VOICEBOX is a MATLAB toolbox for speech processing. Home page is at % http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/voicebox.html % %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % 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 2 of the License, 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. % % You can obtain a copy of the GNU General Public License from % ftp://prep.ai.mit.edu/pub/gnu/COPYING-2.0 or by writing to % Free Software Foundation, Inc.,675 Mass Ave, Cambridge, MA 02139, USA. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% if nargin==1 d=[find(size(x)-1) 1]; d=d(1); end n=size(x,d); if n<=1, y=x; return; end s=size(x); p=[d:ndims(x) 1:d-1]; z=reshape(permute(x,p),n,prod(s)/n); y=max(z); y=y+log(sum(exp(z-y(ones(n,1),:)))); s(d)=1; y=ipermute(reshape(y,s(p)),p);