--- /dev/null
+## Copyright (C) 2000-2012 Bill Lash
+##
+## 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} {@var{b} =} unwrap (@var{x})
+## @deftypefnx {Function File} {@var{b} =} unwrap (@var{x}, @var{tol})
+## @deftypefnx {Function File} {@var{b} =} unwrap (@var{x}, @var{tol}, @var{dim})
+##
+## Unwrap radian phases by adding multiples of 2*pi as appropriate to
+## remove jumps greater than @var{tol}. @var{tol} defaults to pi.
+##
+## Unwrap will work along the dimension @var{dim}. If @var{dim}
+## is unspecified it defaults to the first non-singleton dimension.
+## @end deftypefn
+
+## Author: Bill Lash <lash@tellabs.com>
+
+function retval = unwrap (x, tol, dim)
+
+ if (nargin < 1 || nargin > 3)
+ print_usage ();
+ endif
+
+ if (!isnumeric(x))
+ error ("unwrap: X must be a numeric matrix or vector");
+ endif
+
+ if (nargin < 2 || isempty (tol))
+ tol = pi;
+ endif
+
+ ## Don't let anyone use a negative value for TOL.
+ tol = abs (tol);
+
+ nd = ndims (x);
+ sz = size (x);
+ if (nargin == 3)
+ if (!(isscalar (dim) && dim == fix (dim))
+ || !(1 <= dim && dim <= nd))
+ error ("unwrap: DIM must be an integer and a valid dimension");
+ endif
+ else
+ ## Find the first non-singleton dimension.
+ (dim = find (sz > 1, 1)) || (dim = 1);
+ endif
+
+ rng = 2*pi;
+ m = sz(dim);
+
+ ## Handle case where we are trying to unwrap a scalar, or only have
+ ## one sample in the specified dimension.
+ if (m == 1)
+ retval = x;
+ return;
+ endif
+
+ ## Take first order difference to see so that wraps will show up
+ ## as large values, and the sign will show direction.
+ idx = repmat ({':'}, nd, 1);
+ idx{dim} = [1,1:m-1];
+ d = x(idx{:}) - x;
+
+ ## Find only the peaks, and multiply them by the appropriate amount
+ ## of ranges so that there are kronecker deltas at each wrap point
+ ## multiplied by the appropriate amount of range values.
+ p = ceil(abs(d)./rng) .* rng .* (((d > tol) > 0) - ((d < -tol) > 0));
+
+ ## Now need to "integrate" this so that the deltas become steps.
+ r = cumsum (p, dim);
+
+ ## Now add the "steps" to the original data and put output in the
+ ## same shape as originally.
+ retval = x + r;
+
+endfunction
+
+%!function t = __xassert(a,b,tol)
+%! if (nargin == 1)
+%! t = all(a(:));
+%! else
+%! if (nargin == 2)
+%! tol = 0;
+%! endif
+%! if (any (size(a) != size(b)))
+%! t = 0;
+%! elseif (any (abs(a(:) - b(:)) > tol))
+%! t = 0;
+%! else
+%! t = 1;
+%! endif
+%! endif
+%!endfunction
+%!
+%!test
+%!
+%! i = 0;
+%! t = [];
+%!
+%! r = [0:100]; # original vector
+%! w = r - 2*pi*floor((r+pi)/(2*pi)); # wrapped into [-pi,pi]
+%! tol = 1e3*eps; # maximum expected deviation
+%!
+%! t(++i) = __xassert(r, unwrap(w), tol); #unwrap single row
+%! t(++i) = __xassert(r', unwrap(w'), tol); #unwrap single column
+%! t(++i) = __xassert([r',r'], unwrap([w',w']), tol); #unwrap 2 columns
+%! t(++i) = __xassert([r;r], unwrap([w;w],[],2), tol); #check that dim works
+%! t(++i) = __xassert(r+10, unwrap(10+w), tol); #check r(1)>pi works
+%!
+%! t(++i) = __xassert(w', unwrap(w',[],2)); #unwrap col by rows should not change it
+%! t(++i) = __xassert(w, unwrap(w,[],1)); #unwrap row by cols should not change it
+%! t(++i) = __xassert([w;w], unwrap([w;w])); #unwrap 2 rows by cols should not change them
+%!
+%! ## verify that setting tolerance too low will cause bad results.
+%! t(++i) = __xassert(any(abs(r - unwrap(w,0.8)) > 100));
+%!
+%! assert(all(t));
+%!
+%!test
+%! A = [pi*(-4), pi*(-2+1/6), pi/4, pi*(2+1/3), pi*(4+1/2), pi*(8+2/3), pi*(16+1), pi*(32+3/2), pi*64];
+%! assert (unwrap(A), unwrap(A, pi));
+%! assert (unwrap(A, pi), unwrap(A, pi, 2));
+%! assert (unwrap(A', pi), unwrap(A', pi, 1));
+%!
+%!test
+%! A = [pi*(-4); pi*(2+1/3); pi*(16+1)];
+%! B = [pi*(-2+1/6); pi*(4+1/2); pi*(32+3/2)];
+%! C = [pi/4; pi*(8+2/3); pi*64];
+%! D = [pi*(-2+1/6); pi*(2+1/3); pi*(8+2/3)];
+%! E(:, :, 1) = [A, B, C, D];
+%! E(:, :, 2) = [A+B, B+C, C+D, D+A];
+%! F(:, :, 1) = [unwrap(A), unwrap(B), unwrap(C), unwrap(D)];
+%! F(:, :, 2) = [unwrap(A+B), unwrap(B+C), unwrap(C+D), unwrap(D+A)];
+%! assert (unwrap(E), F);
+%!
+%!test
+%! A = [0, 2*pi, 4*pi, 8*pi, 16*pi, 65536*pi];
+%! B = [pi*(-2+1/6), pi/4, pi*(2+1/3), pi*(4+1/2), pi*(8+2/3), pi*(16+1), pi*(32+3/2), pi*64];
+%! assert (unwrap(A), zeros(1, length(A)));
+%! assert (diff(unwrap(B), 1)<2*pi, true(1, length(B)-1));
+%!
+%!error unwrap()
git://git.creatis.insa-lyon.fr / CreaPhase.git / blobdiff