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function c=comp_wpfbt(f,wtNodes,rangeLoc,ext,interscaling)
%-*- texinfo -*-
%@deftypefn {Function} comp_wpfbt
%@verbatim
%COMP_WPFBT Compute Wavelet Packet Filterbank Tree
% Usage: c=comp_wpfbt(f,wtNodes,ext);
%
% Input parameters:
% f : Input L*W array.
% wtNodes : Filterbank tree nodes (elementary filterbanks) in
% BF order. Length nodeNo cell array of structures.
% ext : Type of the forward transform boundary handling.
%
% Output parameters:
% c : Coefficients stored in cell-array. Each element is one
% subband (matrix with W columns).
%
%@end verbatim
%@strong{Url}: @url{http://ltfat.github.io/doc/comp/comp_wpfbt.html}
%@end deftypefn
% Copyright (C) 2005-2016 Peter L. Soendergaard <peter@sonderport.dk>.
% This file is part of LTFAT version 2.3.1
%
% 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 3 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 should have received a copy of the GNU General Public License
% along with this program. If not, see <http://www.gnu.org/licenses/>.
% Do non-expansve transform if ext=='per'
doPer = strcmp(ext,'per');
% Pre-allocated output
c = cell(sum(cellfun(@(wtEl) numel(wtEl.h),wtNodes)),1);
interscalingfac = 1;
if strcmp('intscale',interscaling)
interscalingfac = 1/2;
elseif strcmp('intsqrt',interscaling)
interscalingfac = 1/sqrt(2);
end
% OLD code doing the scaling directly on filters in the tree
% if do_scale
% for ii=1:numel(wtNodes)
% range = 1:numel(wtNodes{ii}.h);
% range(rangeLoc{ii}) = [];
% wtNodes{ii}.h(range) = cellfun(@(hEl) setfield(hEl,'h',hEl.h/sqrt(2)),wtNodes{ii}.h(range),...
% 'UniformOutput',0);
% end
% end
ca = f;
cOutRunIdx = 1;
cInRunIdxs = [];
% Go over all nodes in breadth-first order
for jj=1:numel(wtNodes)
% Node filters to a cell array
%hCell = cellfun(@(hEl) conj(flipud(hEl.h(:))),wtNodes{jj}.h(:),...
% 'UniformOutput',0);
hCell = cellfun(@(hEl) hEl.h(:),wtNodes{jj}.h(:),'UniformOutput',0);
% Node filters subs. factors
a = wtNodes{jj}.a;
% Node filters initial skips
if(doPer)
%offset = cellfun(@(hEl) 1-numel(hEl.h)-hEl.offset,wtNodes{jj}.h);
offset = cellfun(@(hEl) hEl.offset,wtNodes{jj}.h);
else
offset = -(a-1);
end
filtNo = numel(hCell);
% Run filterbank
c(cOutRunIdx:cOutRunIdx + filtNo-1)=...
comp_filterbank_td(ca,hCell,a,offset,ext);
% Bookeeping. Store idxs of just computed outputs.
outRange = cOutRunIdx:cOutRunIdx+filtNo-1;
% Omit those, which are not decomposed further
outRange(rangeLoc{jj}) = [];
cInRunIdxs = [cInRunIdxs,outRange];
cOutRunIdx = cOutRunIdx + filtNo;
% Prepare input for the next iteration
% Scaling introduced in order to preserve energy
% (parseval tight frame)
if ~isempty(cInRunIdxs)
c{cInRunIdxs(1)} = c{cInRunIdxs(1)}*interscalingfac;
ca = c{cInRunIdxs(1)};
cInRunIdxs(1) = [];
end
end
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