function q = unwrap(p,cutoff)
%UNWRAP Unwrap the phase.
%   UNWRAP(P) unwraps radian phases P by changing absolute 
%   jumps greater than pi to their 2*pi complement.  P can be a 
%   scalar or a vector.
%
%   UNWRAP(P,TOL) uses a jump tolerance of TOL rather
%   than the default TOL = pi.
%
%   See also ANGLE, ARG, ABS.

%   Davide Rocchesso: 1998/02/9

% Convert row vector in a column vector.
rflag = 0; sizp = size(p);
if (sizp(1) == 1) & (sizp(2) > 0),  
   rflag = 1; 
   p = p.';
end;

% Initialize parameters.
nshifts = 0;
perm = 1:length(sizp);
if nargin == 1
   cutoff = pi;     
end;
   
% Unwrap phase angles.
[m, n] = size(p); 

pmin = min(p); pmin = pmin(ones(m, 1), :);   % To force REM to behave.
p = rem(p - pmin, 2 .* pi) + pmin;           % Phases modulo 2*pi.

if m > 1
   b = [p(1, :); diff(p)];                   % Differentiate phases.
else
   b = p;
end
c = -(b > cutoff); d = (b < -cutoff);        % Locations of jumps.
e = (c + d) .* 2 .* pi;                      % Array of 2*pi jumps.
f = cumsum(e);                               % Integrate to get corrections.

q = p + f;                                   % Phases + corrections.

if rflag, q = q.'; end