update packages

[CreaPhase.git] / octave_packages / m / signal / fftconv.m

diff --git a/octave_packages/m/signal/fftconv.m b/octave_packages/m/signal/fftconv.m
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+## Copyright (C) 1994-2012 John W. Eaton
+##
+## This file is part of Octave.
+##
+## Octave is free software; you can redistribute it and/or modify it
+## under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 3 of the License, or (at
+## your option) any later version.
+##
+## Octave is distributed in the hope that it will be useful, but
+## WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+## General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with Octave; see the file COPYING.  If not, see
+## <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn  {Function File} {} fftconv (@var{x}, @var{y})
+## @deftypefnx {Function File} {} fftconv (@var{x}, @var{y}, @var{n})
+## Convolve two vectors using the FFT for computation.
+##
+## @code{c = fftconv (@var{x}, @var{y})} returns a vector of length equal to
+## @code{length (@var{x}) + length (@var{y}) - 1}.
+## If @var{x} and @var{y} are the coefficient vectors of two polynomials, the
+## returned value is the coefficient vector of the product polynomial.
+##
+## The computation uses the FFT by calling the function @code{fftfilt}.  If
+## the optional argument @var{n} is specified, an N-point FFT is used.
+## @seealso{deconv, conv, conv2}
+## @end deftypefn
+
+## Author: KH <Kurt.Hornik@wu-wien.ac.at>
+## Created: 3 September 1994
+## Adapted-By: jwe
+
+function c = fftconv (x, y, n)
+
+  if (nargin < 2 || nargin > 3)
+    print_usage ();
+  endif
+
+  if (! (isvector (x) && isvector (y)))
+    error ("fftconv: both A and B must be vectors");
+  endif
+  la = length (x);
+  lb = length (y);
+  if ((la == 1) || (lb == 1))
+    c = x * y;
+  else
+    lc = la + lb - 1;
+    x(lc) = 0;
+    y(lc) = 0;
+    if (nargin == 2)
+      c = fftfilt (x, y);
+    else
+      if (! isscalar (n))
+        error ("fftconv: N must be a scalar");
+      endif
+      c = fftfilt (x, y, n);
+    endif
+  endif
+
+endfunction
+
+
+%% FIXME: Borrow tests from conv.m.  May need a tolerance on the assert comparison
+%!test
+%!  x = ones(3,1);
+%!  y = ones(1,3);
+%!  b = 2;
+%!  c = 3;
+%!  assert (fftconv (x, x), [1; 2; 3; 2; 1], 5*eps);
+%!  assert (fftconv (y, y), [1, 2, 3, 2, 1], 5*eps);
+%!  assert (fftconv (x, y), [1, 2, 3, 2, 1], 5*eps);
+%!  assert (fftconv (y, x), [1; 2; 3; 2; 1], 5*eps);
+%!  assert (fftconv (c, x), [3; 3; 3], 5*eps);
+%!  assert (fftconv (c, y), [3, 3, 3], 5*eps);
+%!  assert (fftconv (x, c), [3; 3; 3], 5*eps);
+%!  assert (fftconv (y, c), [3, 3, 3], 5*eps);
+%!  assert (fftconv (b, c), 6, 5*eps);
+
+%!test
+%!  a = 1:10;
+%!  b = 1:3;
+%!  assert (size(conv(a,b)), [1, numel(a)+numel(b)-1])
+%!  assert (size(conv(b,a)), [1, numel(a)+numel(b)-1])
+
+%!  a = (1:10).';
+%!  b = 1:3;
+%!  assert (size(conv(a,b)), [numel(a)+numel(b)-1, 1])
+%!  assert (size(conv(b,a)), [numel(a)+numel(b)-1, 1])
+
+%!test
+%!  a = 1:10;
+%!  b = (1:3).';
+%!  assert (size(conv(a,b)), [1, numel(a)+numel(b)-1])
+%!  assert (size(conv(b,a)), [1, numel(a)+numel(b)-1])
+
+%% Test input validation
+%!error fftconv (1);
+%!error fftconv (1,2,3,4);
+%!error fftconv ([1, 2; 3, 4], 3);
+%!error fftconv (2, []);
+%!error fftconv ([1,1], [2,2] , [3, 4]);