On Tuning Recursive Procedures

We propose a methodology of reducing the space requirements of recursive procedures without destroying their fundamental recursive structure. This technique is quite general, and seems to apply to most recursive procedures, particularly those dealing with recursive data structures. A recursive procedure is transformed into three procedures – a shell which is called from the outside, and has the same interface as the original, a recursive procedure with a minimum number of parameters, and no local variables, and a procedure that performs the operations but has no recursive calls. Our methodology was successfully employed in an implementation of a decision support system. The paper also includes results of experiments, in which space was reduced by a factor of up to seven, and run time was also improved.