let initialize_output () = 
      ext "%% ---------------------\n";          
      ext "%%  LaTeX file \n";         
      ext "%% ---------------------\n";        
      ext "%% Created by OCaml\n\n";
      ext "\\documentclass{article}\n\n";
      ext "\\usepackage[latin1]{inputenc}\n";
      ext "\\usepackage[latin1]{pstricks}\n";
      ext (Printf.sprintf "\\usepackage[width=%fcm, height=%fcm, centering]{geometry}\n" 
        !width !height);
      ext "\\usepackage{color}\n";
      ext (Printf.sprintf "\\pagestyle{%s}\n\n" !pagestyle);
      ext "\\begin{document}\n\n"