function coef=haar(vector)
% Haar transform
%
% Syntax COEF=HARR(VECTOR)
% This function returns the Haar wavelet transform of the data in 
% VECTOR.  COEF is thereturned transform and is a column vector of
% length 2^n > length of VECTOR.
%
% Written by Eric Tittley (940901) etittley@phobos.astro.uwo.ca
%
% See also HAAR_INV

if nargin<1 error('Too few arguments passed to haar'); end
if nargin>1 error('Too many arguments passed to haar'); end
n=length(vector);

vector=vector(:);

k=0; flag=1;
while(flag)
 k=k+1;
 if n<=2^k 
  vector=[vector;0*(1&[1:2^k-n]')];
  flag=0; 
 end
end

pow=k;
coef=vector;
for k=1:pow
 avg=[1:2^(pow-k)];
 diff=[1:2^(pow-k)];
 for l=1:2^(pow-k);
  avg(l)=(coef(l*2-1)+coef(l*2))/2;
  diff(l)=(coef(l*2-1)-coef(l*2))/2;
 end
 coef(1:2^(pow-k))=avg;
 coef(2^(pow-k)+1:2^(pow-k+1))=diff;
end