/usr/share/freemat/toolbox/signal/fftn.m is in freemat-data 4.0-5.
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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 | % FFTN FFTN N-Dimensional Forward FFT
%
% Usage
%
% Computes the DFT of an N-dimensional numerical array along all
% dimensions. The general syntax for its use is
%
% y = fftn(x)
%
% which computes the same-size FFTs for each dimension of x.
% Alternately, you can specify the size vector
%
% y = fftn(x,dims)
%
% where dims is a vector of sizes. The array x is zero padded
% or truncated as necessary in each dimension so that the output
% is of size dims. The fftn function is implemented by a sequence
% of calls to fft.
% Copyright (c) 2002-2007 Samit Basu
% Licensed under the GPL
function y = fftn(x,dims)
if (nargin == 1)
dims = size(x);
end
dims = dims(:)';
if (numel(dims) < ndims(x))
pnts = size(x);
dims = [dims,pnts((numel(dims)+1):end)];
end
y = x;
if (~isa(y,'single')) y = double(y); end;
if (numel(y) == 0) return; end;
for n=1:numel(dims)
y = fft(y,dims(n),n);
end
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