function M=reconstruct(X)

%    Reconstruction of 'Lena'
%
%    ===========================================================
%    M=reconstruct(X)
% 
%    This function builds 8 x 8 blocks from the column vectors in 
%    X and put these blocks together in a matrix M.
%    M has dimension 256 x 256.
%    X should have dimension 64 x 1024


for rowblock=1:32         % 256/8
  for colblock=1:32       % 256/8
    Block=reshape(X(:,(rowblock-1)*32+colblock),8,8);
    M((colblock-1)*8+1:colblock*8,(rowblock-1)*8+1:rowblock*8)=Block;
  end
end

    












for rowblock = 1:size(M,1)/8
  for colblock =1:size(M,2)/8
    for rowOfPxls = 1:8
      for colOfPxls = 1:8
	% create block of size 8x8 out of the matrix
	block(rowOfPxls, colOfPxls) = M((rowblock - 1)*8 + ...
	    rowOfPxls, (colblock - 1)*8 + colOfPxls);
      end
    end
    X(:, rowblock + (colblock - 1)*32) = block(:);
  end
end