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// Copyright (C) 2018 - IIT Bombay - FOSSEE
//
// This file must be used under the terms of the CeCILL.
// This source file is licensed as described in the file COPYING, which
// you should have received as part of this distribution. The terms
// are also available at
// http://www.cecill.info/licences/Licence_CeCILL_V2-en.txt
// Original Source : https://octave.sourceforge.io/signal/
// Modifieded by:Sonu Sharma, RGIT Mumbai
// Organization: FOSSEE, IIT Bombay
// Email: toolbox@scilab.in
function [d]=dftmtx(n)
// Computes n-by-n Discrete Fourier transformation matrix
//Calling Sequence
//d=dftmtx(n)
//Parameters
//n: Real positive scalar number
// Description
//This fuction gives a complex matrix of values whose product with a vector produces the discrete Fourier transform. This can also be achieved by directly using the fft function i.e. y=fft(x) is same as y=A*x where A=dftmtx(n).
// Examples
//d = dftmtx(4)
//Output:
// d =
//
// 1. 1. 1. 1.
// 1. - i - 1. i
// 1. - 1. 1. - 1.
// 1. i - 1. - i
funcprot(0);
[nargout nargin] = argn();
if (nargin ~= 1)
error("dftmtx: invalid number of inputs")
elseif (~isscalar(n))
error ("dftmtx: argument must be scalar");
end
c = eye(n, n);
d = [];
for i = 1:n
d = [d fft(c(:, i))]
end
endfunction
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