function wavelet_stem(wname)

%  Makes 'stem plots' of level-4 wavelets and scaling vectors for series of 
%  length 2^4.(assuming periodic extension if necessary)
%  Example call:
%    wavelet_stem('haar')  % Stem plot of Haar wavelets and scaling vectors

  levmax = 4;
  N = 2^levmax; 

  lev = zeros(1,N);
  m = zeros(1,N);
  lev(1:2) = levmax;
  m(1:2) = 1;
  for l=1:(levmax-1)
    joff = 2^(levmax-l);
    lev(joff+1:2*joff)=l;
    m(joff+1:2*joff) = 1:joff;
  end
  I = eye(N);
  W = zeros(N);
  for k = 1:N

    % Wavelet decomp of 1 in k'th sample, 0 otherwise
 
    w = I(k,:);
    for l=1:levmax
      last = 2^(levmax-l+1);
      [w(1:last/2) w((last/2+1):last)] = dwt(w(1:last),wname,'mode','per');
    end
    W(k,:) = w(1:N);
  end
  W = W'; % Now C = W*s, where s is the signal vector
  subplot(N/2,2,1);

  % Stem plot of first half of rows of W

  for j = 1:N/2
    subplot(N/2,2,2*j-1)
    stem(W(j,:));
    axis([0 N -1 1])
    if(j==1)
       type = 'V';
       title(['Level-' int2str(levmax) ' ' wname ' wavelets'])
    else
       type = 'W';
    end
    text(-1,0,[type '_' int2str(m(j)) '^' int2str(lev(j))])
    axis off

    subplot(N/2,2,2*j)
    stem(W(j+N/2,:));
    axis([0 N -1 1])
    type = 'W';
    text(-1,0,[type '_' int2str(m(j+N/2)) '^' int2str(lev(j+N/2))])
    axis off
  end