1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
|
function ff=ref_fac(f,W,c,d,p,q,permutation)
%-*- texinfo -*-
%@deftypefn {Function} ref_fac
%@verbatim
%REF_FAC Reference factorization.
%
% This function cannot handle multidimensional arrays.
% Reshape to matrix BEFORE you call this.
%
%@end verbatim
%@strong{Url}: @url{http://ltfat.github.io/doc/reference/ref_fac.html}
%@end deftypefn
% Copyright (C) 2005-2016 Peter L. Soendergaard <peter@sonderport.dk>.
% This file is part of LTFAT version 2.2.0
%
% 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/>.
% Output
ff=zeros(p*q*W,c*d);
% If d==1, it is not possible to further reduce the size of
% wk. Actually, some of the following code produces an
% error, because Matlab interprets an fft of a 1x q*W*p as a
% a row operation !
if d>1
% Shape to match first fft pass.
work=zeros(d,q*W*p);
% This loop iterates over the number of truly different wk's.
for ko=0:c-1
% Permute and copy into work array.
% Format is suited for fft.
work(:)=f(permutation+ko,:);
% Execute the fft and place transposed in ff.
ff(:,1+ko*d:(ko+1)*d)=fft(work.',[],2);
end;
else
% Work arrays.
work=zeros(p*q*W,1);
for ko=0:c-1
% Permute input.
work(:)=f(permutation+ko,:);
% Write the block.
ff(:,ko+1)=work;
end
end;
|
