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|
; Defsort - Defines a stable sort when given a comparison function
; Copyright (C) 2008 Centaur Technology
;
; Contact:
; Centaur Technology Formal Verification Group
; 7600-C N. Capital of Texas Highway, Suite 300, Austin, TX 78731, USA.
; http://www.centtech.com/
;
; License: (An MIT/X11-style license)
;
; Permission is hereby granted, free of charge, to any person obtaining a
; copy of this software and associated documentation files (the "Software"),
; to deal in the Software without restriction, including without limitation
; the rights to use, copy, modify, merge, publish, distribute, sublicense,
; and/or sell copies of the Software, and to permit persons to whom the
; Software is furnished to do so, subject to the following conditions:
;
; The above copyright notice and this permission notice shall be included in
; all copies or substantial portions of the Software.
;
; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
; IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
; FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
; AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
; LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
; FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
; DEALINGS IN THE SOFTWARE.
;
; Original author: Jared Davis <jared@centtech.com>
(in-package "ACL2")
(include-book "uniquep")
(defund remove-adjacent-duplicates (x)
(declare (xargs :guard t))
(cond ((atom x)
nil)
((atom (cdr x))
(list (car x)))
((equal (car x) (cadr x))
(remove-adjacent-duplicates (cdr x)))
(t
(cons (car x)
(remove-adjacent-duplicates (cdr x))))))
(defthm true-listp-of-remove-adjacent-duplicates
(true-listp (remove-adjacent-duplicates x))
:rule-classes :type-prescription)
(defthm consp-of-remove-adjacent-duplicates
(equal (consp (remove-adjacent-duplicates x))
(consp x))
:hints(("Goal" :in-theory (enable remove-adjacent-duplicates))))
(defthm remove-adjacent-duplicates-under-iff
(iff (remove-adjacent-duplicates x)
(consp x))
:hints(("Goal" :in-theory (enable remove-adjacent-duplicates))))
(defthm member-equal-of-remove-adjacent-duplicates
(iff (member-equal a (remove-adjacent-duplicates x))
(member-equal a x))
:hints(("Goal" :in-theory (enable remove-adjacent-duplicates))))
(defthm no-duplicatesp-equal-of-remove-adjacent-duplicates
(implies (<<-ordered-p x)
(no-duplicatesp-equal (remove-adjacent-duplicates x)))
:hints(("Goal" :in-theory (enable remove-adjacent-duplicates
<<-ordered-p))))
(defund remove-dups (x)
(declare (xargs :guard (true-listp x)))
(remove-adjacent-duplicates (<<-sort x)))
(defthm true-listp-of-remove-dups
(equal (true-listp (remove-dups x))
t)
:hints(("Goal" :in-theory (enable remove-dups))))
(encapsulate
()
(local (defthm member-equal-is-duplicity
(iff (member-equal a x)
(< 0 (duplicity a x)))
:hints(("Goal" :in-theory (enable duplicity)))))
(defthm member-equal-of-<<-sort
(iff (member-equal a (<<-sort x))
(member-equal a x))))
(defthm member-equal-of-remove-dups
(iff (member-equal a (remove-dups x))
(member-equal a x))
:hints(("Goal" :in-theory (enable remove-dups))))
(defthm no-duplicatesp-equal-of-remove-dups
(no-duplicatesp-equal (remove-dups x))
:hints(("Goal" :in-theory (enable remove-dups))))
#||
(include-book
"remove-dups")
(include-book "misc/hons-help" :dir :system)
:q
(ccl::set-lisp-heap-gc-threshold (expt 2 34))
(defparameter *integers1*
;; A test vector of 10,000 integers with many duplicates
(loop for j from 1 to 10
nconc
(loop for i from 1 to 1000 collect i)))
(defparameter *integers2*
;; A test vector of 10,000 integers with no duplicates
(loop for i from 1 to 10000 collect i)))
;; 5.3 seconds, 1.5 GB allocated
(prog2$ (ccl::gc)
(time (loop for i fixnum from 1 to 1000
do
(let ((result (remove-dups *integers1*)))
(declare (ignore result))
nil))))
;; 2.0 seconds, 117 MB allocated
(prog2$ (ccl::gc)
(time (loop for i fixnum from 1 to 1000
do
(let ((result (hons-remove-duplicates *integers1*)))
(declare (ignore result))
nil))))
;; 0.49 seconds, 135 MB allocated
(prog2$ (ccl::gc)
(time (loop for i fixnum from 1 to 100
do
(let ((result (remove-dups *integers2*)))
(declare (ignore result))
nil))))
;; 1.1 seconds, 128 MB allocated
(prog2$ (ccl::gc)
(time (loop for i fixnum from 1 to 100
do
(let ((result (hons-remove-duplicates *integers2*)))
(declare (ignore result))
nil))))
||#
|
