findpeaks(y)

function [ind,peaks] = findpeaks(y)
% FINDPEAKS  Find peaks in real vector.
%  ind = findpeaks(y) finds the indices (ind) which are
%  local maxima in the sequence y.  
%
%  [ind,peaks] = findpeaks(y) returns the value of the peaks at 
%  these locations, i.e. peaks=y(ind);

% Copyright 2002 - 2003 The MathWorks, Inc

y = y(:)';

switch length(y)
case 0
    ind = [];
case 1
    ind = 1;
otherwise
    dy = diff(y);
    not_plateau_ind = find(dy~=0);
    ind = find( ([dy(not_plateau_ind) 0]<0) & ([0 dy(not_plateau_ind)]>0) );
    ind = not_plateau_ind(ind);
    if y(1)>y(2)
        ind = [1 ind];
    end
    if y(end-1)<y(end)
        ind = [ind length(y)];
    end
end

if nargout > 1
    peaks = y(ind);
end