function outsig=ufilterbankz(b,a,insig,hopsize)
%UFILTERBANKZ  Uniform Filter bank with zero boundary condition
%   Usage: outsig=ufilterbankz(b,a,insig);
%          outsig=ufilterbankz(b,a,insig,hopsize);
%
%   UFILTERBANKZ(b,a,insig) filters the input signal with the filters
%   described in a and b.
%
%   UFILTERBANKZ(b,a,insig,hopsize) does the same, but only outputs every
%   hopsize sample in the time domain.
%
%   If a and b are matrices then each row corresponds to a subband
%   channel.
%
%   If insig is a matrix then filtering is applied along the columns.
%
%   If f is a single vector, then the output will be a matrix, where each
%   column in f is filtered by the corresponding filter in g. If f is
%   a matrix, the output will be 3-dimensional, and the third dimension will
%   correspond to the columns of the input signal
%   See also: gammatone, filterbankz, auditoryfilterbank
%
%   Url: http://amtoolbox.org/amt-1.3.0/doc/common/ufilterbankz.php

%   #Author : Peter L. Søndergaard

% This file is licensed unter the GNU General Public License (GPL) either 
% version 3 of the license, or any later version as published by the Free Software 
% Foundation. Details of the GPLv3 can be found in the AMT directory "licences" and 
% at <https://www.gnu.org/licenses/gpl-3.0.html>. 
% You can redistribute this file and/or modify it under the terms of the GPLv3. 
% This file is distributed without any warranty; without even the implied warranty 
% of merchantability or fitness for a particular purpose. 
  

%% ------ Checking of input parameters ---------  

narginchk(3,4);

if nargin==3
  hopsize=1;
end;


%% ------ Computation --------------------------

[insig,siglen,dummy,nsigs,dim,permutedsize,order]=assert_sigreshape_pre(insig,[],[], ...
                                                  upper(mfilename));
nchannels=size(b,1);

outlen=ceil(siglen/hopsize);

outsig=zeros(outlen,nchannels,nsigs);

for ii=1:nchannels
  res = filter(b(ii,:),a(ii,:),insig);
  res = res(1:hopsize:siglen,:);  
  outsig(:,ii,:) = reshape(res,outlen,1,nsigs);
end;

% Modify permutedsize and order to reflect that first dimension has split
% in two
permutedsize=[outlen,nchannels,permutedsize(2:end)];
order=assert_groworder(order);

outsig=assert_sigreshape_post(outsig,dim,permutedsize,order);