--- a/scripts/signal/unwrap.m	Thu Feb 25 10:37:59 2016 -0800
+++ b/scripts/signal/unwrap.m	Tue Mar 01 13:15:08 2016 -0800
@@ -21,8 +21,8 @@
 ## @deftypefnx {} {@var{b} =} unwrap (@var{x}, @var{tol})
 ## @deftypefnx {} {@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}.
+## Unwrap radian phases by adding or subtracting multiples of 2*pi as
+## appropriate to remove jumps greater than @var{tol}.
 ##
 ## @var{tol} defaults to pi.
 ##
@@ -80,7 +80,7 @@
   ## 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));
+  p = round (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);
@@ -92,53 +92,43 @@
 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
-%!
+%!shared i, t, r, w, tol
 %! 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));
-%!
+%! r = [0:100];                         ## original vector
+%! w = r - 2*pi*floor ((r+pi)/(2*pi));  ## wrapped into [-pi,pi]
+%! tol = 1e3*eps;
+
+%!assert (r,  unwrap (w),  tol)
+%!assert (r', unwrap (w'), tol)
+%!assert ([r',r'], unwrap ([w',w']), tol)
+%!assert ([r; r ], unwrap ([w; w ], [], 2), tol)
+%!assert (r + 10, unwrap (10 + w), tol)
+
+%!assert (w', unwrap (w', [], 2))
+%!assert (w,  unwrap (w,  [], 1))
+%!assert ([w; w], unwrap ([w; w]))
+
+## Test that small values of tol have the same effect as tol = pi
+%!assert (r, unwrap (w, 0.1), tol)
+%!assert (r, unwrap (w, eps), tol)
+
+## Test that phase changes larger than 2*pi unwrap properly
+%!assert ([0;  1],        unwrap ([0;  1]))
+%!assert ([0;  4 - 2*pi], unwrap ([0;  4]))
+%!assert ([0;  7 - 2*pi], unwrap ([0;  7]))
+%!assert ([0; 10 - 4*pi], unwrap ([0; 10]))
+%!assert ([0; 13 - 4*pi], unwrap ([0; 13]))
+%!assert ([0; 16 - 6*pi], unwrap ([0; 16]))
+%!assert ([0; 19 - 6*pi], unwrap ([0; 19]))
+%!assert (max (abs (diff (unwrap (100*pi * rand (1000, 1))))) < pi)
+
 %!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));
-%!
+%! 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)];
@@ -148,13 +138,16 @@
 %! 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);
-%!
+%! 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));
+%! assert (unwrap (A), zeros (1, length (A)))
+%! assert (diff (unwrap (B), 1) < 2*pi, true (1, length (B)-1))
 
-%!error unwrap()
+## Test input validation
+%!error unwrap ()
+%!error unwrap (1,2,3,4)
+%!error unwrap ("foo")