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function x=fft2(varargin)
// Copyright INRIA
// Two-dimensional fast Fourier transform
// Syntax : y = fft2(x) or y = fft2(x,m,n)
// Inputs :
// x : scalar, vector, matrix, array (real or complex)
// m, n : numbers (respectively) of rows and colums of x which used for the perfom of DFT,if the rows number respectively (columns) of x is more than m then x is truncated in order to have m rows, else if the rows (respectively columns) number of x is less than m then x rows are completed by 0 to have m rows.
//
// Outputs :
// y : scalar, vector, matrix, array (real or complex), if there is one input argument x then y and x have the same size, else if there are 3 inputs arguments then the sizes of the first and second dimension of y are equal to m and n, the others dimension sizes are equal to the size of x
// F.B
if size(varargin) == 1 then
a = varargin(1);
if type(a) == 1 then
x = fft(a);
elseif typeof(a) == 'hypermat' then
dims = matrix(x.dims,-1,1);
v = matrix(x.entries,-1,1);
incr = 1;
for k=1:2
dk = double(dims(k));
v = fft(v ,-1,dk,incr);
incr = incr*dk;
end
x = matrix(v,double(dims));
end
elseif size(varargin) == 3 then
a = varargin(1);
m = varargin(2);
n = varargin(3);
asize1 = size(a,1);
asize2 = size(a,2);
if type(a) == 1 then
x(1:min(m,asize1),1:asize2)=a(1:min(m,asize1),1:asize2);
elseif typeof(a) == 'hypermat' then
dims = matrix(a.dims,-1,1);
dims = double(dims);
dims(1) = m;
dims(2) = n;
x=hypermat(dims)
for i=1:prod(dims(3:$))
x(1:min(m,asize1),1:min(n,asize2),i)=a(1:min(m,asize1),1:min(n,asize2),i);
end
end
x=fft2(x);
else error("wrong number of input arguments");
end
endfunction
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