share/algebra/charsets/fateman-len.lisp

   1 ;; from Fateman
   2
   3
   4 (in-package :maxima)
   5
   6 (defun $charsets_polylength (x)
   7    (let ((y (ratf x)))
   8    (+ (cp1 (cadr y)) ;numerator
   9       (cp1 (cddr y))))) ;denominator
  10
  11 (defun cp1(p)
  12    ;; sum up  the sizes of the terms in the rational form polynomial p
  13    (if (pcoefp p) (flatsize p)            ; a constant's length in
  14 decimal chars
  15         (let ((count 0))
  16        (do ((i (cdr p)(cddr i)))
  17            ((null i) (1+ count))  ; one more for the variable name
  18          (incf count (flatsize (car i))) ; length of exponent
  19          (incf count (cp1 (cadr i))) ; length of coefficient, recursively
  20         ))))
  21
  22
  23 ;; Tests:
  24 #|
  25 pl(x):=charsets_polylength(x)         ;
  26 pl( (2*x^3*y^5+3*y*z^2)/5)         ; 12
  27 pl(x+y)                 ; 8
  28 pl(2*x)                 ; 4
  29 pl(2*x^2*y^3)                 ; 6
  30 |#
  31 ;; This is NOT the same as Maple, but I am guessing that it is
  32 ;; a satisfactory ranking of complexity for the
  33 ;; characteristic set method.    RJF
  34