// Scilab ( http://www.scilab.org/ ) - This file is part of Scilab
// Copyright (C) INRIA - F.B
//
// 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_V2.1-en.txt
//
function x=fft2(varargin)
    // 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


    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(msprintf(gettext("%s: Wrong number of input arguments: %d or %d expected.\n"),"fft2",1,3));
    end
endfunction