80 lines
2.9 KiB
Scheme
80 lines
2.9 KiB
Scheme
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;;; File: dderiv.sc
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;;; Description: DDERIV benchmark from the Gabriel tests
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;;; Author: Vaughan Pratt
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;;; Created: 8-Apr-85
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;;; Modified: 10-Apr-85 14:53:29 (Bob Shaw)
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;;; 23-Jul-87 (Will Clinger)
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;;; 9-Feb-88 (Will Clinger)
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;;; 21-Mar-94 (Qobi)
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;;; 31-Mar-98 (Qobi)
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;;; 26-Mar-00 (flw)
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;;; Language: Scheme (but see note below)
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;;; Status: Public Domain
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;;; Note: This benchmark uses property lists. The procedures that must
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;;; be supplied are get and put, where (put x y z) is equivalent to Common
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;;; Lisp's (setf (get x y) z).
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;;; DDERIV -- Symbolic derivative benchmark written by Vaughan Pratt.
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;;; This benchmark is a variant of the simple symbolic derivative program
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;;; (DERIV). The main change is that it is `table-driven.' Instead of using a
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;;; large COND that branches on the CAR of the expression, this program finds
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;;; the code that will take the derivative on the property list of the atom in
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;;; the CAR position. So, when the expression is (+ . <rest>), the code
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;;; stored under the atom '+ with indicator DERIV will take <rest> and
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;;; return the derivative for '+. The way that MacLisp does this is with the
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;;; special form: (DEFUN (FOO BAR) ...). This is exactly like DEFUN with an
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;;; atomic name in that it expects an argument list and the compiler compiles
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;;; code, but the name of the function with that code is stored on the
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;;; property list of FOO under the indicator BAR, in this case. You may have
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;;; to do something like:
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;;; :property keyword is not Common Lisp.
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(define (dderiv-aux a) (list '/ (dderiv a) a))
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(define (+dderiv a) (cons '+ (map dderiv a)))
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(put '+ 'dderiv +dderiv) ; install procedure on the property list
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(define (-dderiv a) (cons '- (map dderiv a)))
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(put '- 'dderiv -dderiv) ; install procedure on the property list
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(define (*dderiv a) (list '* (cons '* a) (cons '+ (map dderiv-aux a))))
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(put '* 'dderiv *dderiv) ; install procedure on the property list
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(define (/dderiv a)
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(list '-
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(list '/ (dderiv (car a)) (cadr a))
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(list '/
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(car a)
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(list '* (cadr a) (cadr a) (dderiv (cadr a))))))
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(put '/ 'dderiv /dderiv) ; install procedure on the property list
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(define (dderiv a)
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(cond ((not (pair? a)) (cond ((eq? a 'x) 1) (else 0)))
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(else (let ((dderiv (get (car a) 'dderiv)))
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(cond (dderiv (dderiv (cdr a)))
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(else 'error))))))
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(define (run)
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(do ((i 0 (+ i 1))) ((= i 1000))
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(dderiv '(+ (* 3 x x) (* a x x) (* b x) 5))
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(dderiv '(+ (* 3 x x) (* a x x) (* b x) 5))
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(dderiv '(+ (* 3 x x) (* a x x) (* b x) 5))
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(dderiv '(+ (* 3 x x) (* a x x) (* b x) 5))
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(dderiv '(+ (* 3 x x) (* a x x) (* b x) 5))))
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;(time (do ((i 10 (- i 1))) ((zero? i)) (run)))
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(run)
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(display (dderiv '(+ (* 3 x x) (* a x x) (* b x) 5)))
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(newline)
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