  ifft
  Builtin Function



      SSyynnooppssiiss
        Inverse Discrete Fourier Transform

      SSyynnttaaxx
        ifft ( _X )

        ifft ( _X, _N )

      DDeessccrriippttiioonn
        Ifft utilizes the FFTPACK subroutine CFFTB to compute a discrete
        Fourier transform of the input. The output is scaled by 1/N, so
        that a call to fft() followed by a call to ifft() will reproduce
        the original input.

        If ifft is used with a second argument, _N, then the matrix _X is
        either padded with zeros, or truncated till it is of length _N
        (if _X is a vector), or has row dimension _N (if it is a matrix).

        Subroutine CFFTB computes the backward complex discrete Fourier
        transform (the Fourier synthesis). equivalently, CFFTB computes
        a complex periodic sequence from its Fourier coefficients.



                  for j=1,...,n

                     c(j)=the sum from k=1,...,n of

                           c(k)*exp(i*(j-1)*(k-1)*2*pi/n)

                                   where i=sqrt(-1)





     The argument _X must be a matrix. If _X is a row, or column matrix
     then a vector ifft is performed. If _X is a MxN matrix then the N
     columns of _X are ifft'ed.


     SSeeee AAllssoo
        fft


















