From: tk@ic.unicamp.br   
      
   > is it always correct, that the Strahler number of an expression tree   
   > denotes the minimal number of registers needed? The link in wikipedia   
   > referring to the original source is apparently broken. However IMHO the   
   > Strahler number can only be applied if the tree contains binary   
   > expressions only (which may not be the case anymore with e.g. fused   
   > multiply-add operations).   
      
   Strahler numbers work as long as you have an expression tree.  It is a   
   very simple task to adapt the algorithm for operators with any any   
   arity: unary, binary, ternary and so on.   
      
   -- Tomasz Kowaltowski   
   [How does it compare to Sethi-Ullman numbering? -John]   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)