1;;; -*-  Mode: Lisp; Package: Maxima; Syntax: Common-Lisp; Base: 10 -*- ;;;;
2;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
3;;;     The data in this file contains enhancments.                    ;;;;;
4;;;                                                                    ;;;;;
5;;;  Copyright (c) 1984,1987 by William Schelter,University of Texas   ;;;;;
6;;;     All rights reserved                                            ;;;;;
7;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
8;;;     (c) Copyright 1982 Massachusetts Institute of Technology         ;;;
9;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
10
11(in-package :maxima)
12
13(macsyma-module ratout)
14
15;; THIS IS THE OUT-OF-CORE SEGMENT OF THE RATIONAL FUNCTION PACKAGE.
16
17(declare-top (special $algebraic varlist ss *y* f $factorflag modulus
18		      genvar *alpha *x* *p *max *var *res *chk *l
19		      $ratfac u* $ratwtlvl *ratweights $ratweights))
20
21(declare-top (special xv bigf1 bigf2
22		      gcd $factorflag))
23
24;;	NEWGCD (X,Y) RETURNS A LIST OF THREE ITEMS,
25;;	(GCD, X/GCD, Y/GCD)
26
27(defun newgcd (x y modulus)
28  (set-modulus modulus)
29  (let ((a (cond ((pcoefp x)
30		  (cond ((zerop x) y)
31			((pcoefp y) (cgcd x y))
32			(t (pcontent1 (cdr y) x))))
33		 ((pcoefp y) (cond ((zerop y) x) (t (pcontent1 (cdr x) y))))
34		 ((pointergp (p-var x) (p-var y)) (oldcontent1 (cdr x) y))
35		 ((pointergp (p-var y) (p-var x)) (oldcontent1 (cdr y) x))
36		 (t nil))))
37    (cond (a (list a (pquotient x a) (pquotient y a)))
38	  (modulus (pgcdp x y modulus))
39	  (t (pgcdm x y)))))
40
41;;;***	PMODCONTENT COMPUTES CONTENT OF
42;;;	P IN
43;;	Z [X ] [X , X , ..., X   ]
44;;        P  V    1   2        V-1
45
46;;	PMODCONTENT OF 3*A*X IS A, IF MAINVAR IS X (=X )
47;;						      V
48
49(defun pmodcontent (p)
50  (prog (*var *chk *res *max gcd)
51     (setq *chk (car p))
52     (setq *max 0)
53     (setq *var (pnext (cdr p) nil))
54     (cond ((pointergp xv *chk) (go ret1))
55	   ((null *var) (return (list p 1))))
56     (pgath1 (cdr p))
57     a    (setq *res 0)
58     (pgath3 (cdr p))
59     a2   (cond ((pcoefp *res) (cond ((pzerop *res) nil)(t(go ret1))))
60		((not (eq (car *res) *chk)) (go ret1))
61		((not (univar (cdr *res)))
62		 (setq *res (car (pmodcontent *res)))
63		 (go a2))
64		(gcd (setq gcd (pgcdu gcd *res)))
65		(t (setq gcd *res)))
66     (cond ((pcoefp gcd) (go ret1))
67	   ((minusp (setq *max (1- *max)))
68	    (return (list gcd (pquotient p gcd)))))
69     (go a)
70     ret1 (return (list 1 p))))
71
72(defun pgathercoef (p *chk *res)
73  (if (not (eq (car p) *chk)) 1 (pgath2 (cdr p) nil)))
74
75(defun pgath1 (p)
76  (prog nil
77     (cond ((null p) (return *max))
78	   ((pcoefp (cadr p)) nil)
79	   ((eq (caadr p) *var) (setq *max (max *max (cadadr p)))))
80     (return (pgath1 (cddr p)))))
81
82(defun pgath2 (p vmax)
83  (prog (v2)
84     (cond ((null p) (return *res))
85	   ((pcoefp (cadr p)) nil)
86	   ((vgreat (setq v2 (pdegreer (cadr p))) vmax)
87	    (setq *res (psimp *chk
88			      (list (car p) (leadcoefficient (cadr p)))))
89	    (setq vmax v2))
90	   ((equal vmax v2)
91	    (setq *res
92		  (pplus *res
93			 (psimp *chk
94				(list (car p) (leadcoefficient (cadr p))))))))
95     (return (pgath2 (cddr p) vmax))))
96
97(defun pgath3 (p)
98  (prog (zz)
99     (cond ((null p) (return *res))
100	   ((pcoefp (cadr p))
101	    (cond ((equal *max 0) (setq zz (cadr p)) (go add)) (t (go ret))))
102	   ((eq (caadr p) *var) (setq zz (ptterm (cdadr p) *max)) (go add)))
103     (cond ((equal *max 0) (setq zz (cadr p))) (t (go ret)))
104     add  (cond ((equal zz 0) (go ret)))
105     (setq *res (pplus *res (psimp *chk (list (car p) zz))))
106     ret  (return (pgath3 (cddr p)))))
107
108(defun pnext (x *l)
109  (pnext1 x)
110  (cond ((null *l) nil)
111	(t (car (sort *l #'pointergp)))))
112
113(defun pnext1 (x)
114  (prog nil
115     (cond ((null x) (return *l))
116	   ((or (pcoefp (cadr x)) (member (caadr x) *l :test #'eq)) nil)
117	   (t (setq *l (cons (caadr x) *l))))
118     (return (pnext1 (cddr x)))))
119
120(defun vgreat (x y)
121  (cond ((null x) nil)
122	((null y) t)
123	((pointergp (car x)(car y))t)
124	((not (eq (car x)(car y)))nil)
125	((> (cadr x)(cadr y)) t)
126	((equal (cadr x)(cadr y))(vgreat (cddr x)(cddr y)))
127	(t nil)))
128
129(defun pdegreer (x)
130  (if (pcoefp x) () (cons (car x) (cons (cadr x) (pdegreer (caddr x))))))
131
132;;***	PGCDP CORRESPONDS TO BROWN'S ALGORITHM P
133
134(defun pgcdp (bigf1 bigf2 modulus)
135  (prog (c c1		c2		n		q
136	 h1tilde	h2tilde		gstar		h1star
137	 h2star		xv		e		b
138	 gbar		nubar		nu1bar		nu2bar
139	 gtilde		f1tilde		f2tilde		biggtilde
140	 degree		f1		f1f2)
141     (set-modulus modulus)
142     (cond ((and (univar (cdr bigf1)) (univar (cdr bigf2)))
143	    (setq q (pgcdu bigf1 bigf2))
144	    (return (list q (pquotient bigf1 q) (pquotient bigf2 q)))))
145     (setq xv (car bigf1))
146     (setq bigf1 (pmodcontent bigf1))
147     (setq bigf2 (pmodcontent bigf2))
148     (setq c (pgcdu (setq c1 (car bigf1)) (setq c2 (car bigf2))))
149     (setq bigf1 (cadr bigf1))
150     (setq bigf2 (cadr bigf2))
151     (setq n 0)
152     (setq e (pdegreer bigf2))
153     (setq degree (pdegreer bigf1))
154     (cond ((vgreat e degree) (setq e degree)))
155     (setq b (ash modulus -1))
156     (setq gbar
157	   (pgcdu (setq f1 (pgathercoef bigf1 xv 0))
158		  (setq f1f2
159			(pgathercoef bigf2 xv 0))))
160     (cond ((equal 0 f1f2) (go step15a)))
161     (setq nubar (pdegree gbar xv))
162     (setq nu1bar (+ nubar (pdegree bigf1 xv)))
163     (setq nu2bar (+ nubar (pdegree bigf2 xv)))
164     (setq f1f2 (ptimes f1 f1f2))
165     (setq nubar (max nu1bar nu2bar))
166     step6(setq b (cplus b 1))
167     (cond ((equal (pcsubst f1f2 b xv) 0) (go step6)))
168     ;; Step 7
169     (setq gtilde (pcsubst gbar b xv))
170     (setq f1tilde (pcsubst bigf1 b xv))
171     (setq f2tilde (pcsubst bigf2 b xv))
172     (setq biggtilde
173	   (ptimeschk gtilde
174		      (car (setq h2tilde (newgcd f1tilde f2tilde modulus)))))
175     (cond ((pcoefp biggtilde) (go step15a)))
176     (setq h1tilde (cadr h2tilde))
177     (setq h2tilde (caddr h2tilde))
178     (setq degree (pdegreer biggtilde))
179     (cond ((vgreat degree e) (go step6))
180	   ((vgreat e degree) (setq n 0) (setq e degree)))
181     (setq n (1+ n))
182     (cond ((equal n 1) (setq q (list xv 1 1 0 (cminus b)))
183	    (setq gstar biggtilde)
184	    (setq h1star h1tilde)
185	    (setq h2star h2tilde))
186	   (t (setq gstar (lagrange33 gstar biggtilde q b))
187	      (setq h1star (lagrange33 h1star h1tilde q b))
188	      (setq h2star (lagrange33 h2star h2tilde q b))
189	      (setq q (ptimes q (list xv 1 1 0 (cminus b))))))
190     ;; Step 12
191     (cond ((not (> n nubar)) (go step6)))
192     ;; Step 13
193     (cond ((or (not (= nu1bar (+ (setq degree (pdegree gstar xv))
194				   (pdegree h1star xv))))
195		(not (= nu2bar (+ degree (pdegree h2star xv)))))
196	    (setq n 0)
197	    (go step6)))
198     (setq gstar (cadr (pmodcontent gstar)))
199     ;; Step 15
200     (setq q (pgathercoef gstar xv 0))
201     (return (monicgcd  (ptimeschk c gstar)
202			(ptimeschk (pquotient c1 c) (pquotientchk h1star q))
203			(ptimeschk (pquotient c2 c) (pquotientchk h2star q))
204			(leadcoefficient gstar)))
205     step15a
206     (return (list c
207		   (ptimeschk (pquotient c1 c) bigf1)
208		   (ptimeschk (pquotient c2 c) bigf2))) ))
209
210
211(defun monicgcd (gcd x y lcf)
212  (cond ((equal lcf 1) (list gcd x y))
213	(t (list	(ptimes (crecip lcf) gcd)
214			(ptimes lcf x)
215			(ptimes lcf y) )) ))
216
217;;***	PGCDM CORRESPONDS TO BROWN'S ALGORITHM M
218
219
220(defun pgcdm
221    (bigf1 bigf2)
222  (prog (c c1		c2		f1		f2	n
223	 e		degree		mubar		p
224	 gtilde		h1tilde		h2tilde
225	 modulus
226	 biggtilde	q		h1star		h2star
227	 gstar		xv              gbar)
228     (setq p *alpha)
229     (setq xv (car bigf1))
230     ;; Step 1
231     (setq f1 (pcontent bigf1))
232     (setq f2 (pcontent bigf2))
233     (setq c (cgcd (setq c1 (car f1)) (setq c2 (car f2))))
234     (setq bigf1 (cadr f1))
235     (setq bigf2 (cadr f2))
236     ;; Step 3
237     (setq f1 (leadcoefficient bigf1))
238     (setq f2 (leadcoefficient bigf2))
239     (setq gbar (cgcd f1 f2))
240     ;; Step 4
241     (setq n 0)
242     (setq degree (pdegreer bigf1))
243     (setq e (pdegreer bigf2))
244     (cond ((vgreat e degree) (setq e degree)))
245     ;; Step 5
246     (setq mubar
247	   (* 2 gbar (max (maxcoefficient bigf1)
248			      (maxcoefficient bigf2))))
249     (go step6a)
250     step6(setq p (newprime p))
251     step6a
252     (cond ((or (zerop (rem f1 p)) (zerop (rem f2 p)))
253	    (go step6)))
254     (set-modulus p)
255     ;; Step 7
256     (setq gtilde (pmod gbar))
257     ;; Step 8
258     (setq biggtilde
259	   (ptimeschk gtilde
260		      (car (setq h2tilde
261				 (newgcd (pmod bigf1) (pmod bigf2)
262					 modulus)))))
263     (cond ((pcoefp biggtilde) (setq modulus nil)
264	    (setq gstar 1)
265	    (setq h1star bigf1)
266	    (setq h2star bigf2)
267	    (go step15)))
268     (cond ((null (cdr h2tilde))
269	    (setq h1tilde (pquotient (pmod bigf1) (car h2tilde)))
270	    (setq h2tilde (pquotient (pmod bigf2) (car h2tilde))))
271	   (t (setq h1tilde (cadr h2tilde))
272	      (setq h2tilde (caddr h2tilde))))
273     (setq degree (pdegreer biggtilde))
274     (cond ((vgreat degree e) (go step6))
275	   ((vgreat e degree) (setq n 0) (setq e degree)))
276     (setq n (1+ n))
277     ;; Step 11
278     (set-modulus nil)
279     (cond ((equal n 1) (setq q p)
280	    (setq gstar biggtilde)
281	    (setq h1star h1tilde)
282	    (setq h2star h2tilde))
283	   (t (setq gstar (lagrange3 gstar biggtilde p q))
284	      (setq h1star (lagrange3 h1star h1tilde p q))
285	      (setq h2star (lagrange3 h2star h2tilde p q))
286	      (setq q (* p q))))
287     ;; Step 12
288     (cond ((> mubar q) (go step6)))
289     (cond ((> (* 2 (max (* (setq gtilde (norm gstar)) (maxcoefficient h1star))
290			 (* gtilde (maxcoefficient h2star))))
291	       q)
292	    (go step6)))
293     (set-modulus nil)
294     (setq gstar (cadr (pcontent gstar)))
295     step15
296     (setq q (leadcoefficient gstar))
297     (return (list (ptimeschk c gstar)
298		   (ptimeschk (cquotient c1 c) (pquotientchk h1star q))
299		   (ptimeschk (cquotient c2 c) (pquotientchk h2star q))))))
300
301;;	THE FUNCTIONS ON THIS PAGE ARE USED BY KRONECKER FACTORING
302
303(defun pkroneck (p)
304  (prog (maxexp i l *p factors factor)
305     (setq maxexp (quotient (cadr p) 2))
306     (setq i 1)
307     a    (when (> i maxexp) (return (cons p factors)))
308     (setq l (p1 (reverse (let ((p p) (i i) ($factorflag t))
309			    (pfactor2 p i)))))
310     b    (when (null l) (go d))
311     (setq *l (car l))
312     (setq *p (car p))
313     (ignore-rat-err
314       (setq factor (errset (pinterpolate *l *p))))
315     (setq l (cdr l))
316     (if (atom factor)
317	 (go b)
318	 (setq factor (car factor)))
319     (when (or (pcoefp factor)
320	       (not (equal (car p) (car factor)))
321	       (not (pzerop (prem p factor))))
322       (go b))
323     (cond (modulus (pmonicize (cdr factor)))
324	   ((pminusp factor) (setq factor (pminus factor))))
325     (setq p (pquotient p factor))
326     (setq maxexp (quotient (cadr p) 2))
327     (setq factors (cons factor factors))
328     (go a)
329     d    (incf i)
330     (go a)))
331
332(defun pfactor2 (p i)
333  (cond ((< i 0) nil)
334	(t (cons (pfactor (pcsubst p i (car p)))
335		 (pfactor2 p (1- i))))))
336
337(defun rpowerset (x n)
338  (cond ((null x) (quote (1 nil)))
339	((equal x 1) (quote (1)))
340	(t (cons 1 (ptts1 x n x)))))
341
342
343(defun allprods (x y)
344  (cond ((null x) nil)
345	((null y) nil)
346	(t (nconc (ap1 (car x) y) (allprods (cdr x) y)))))
347
348(defun al1 (f r len)
349  (prog (ss)
350     (cond
351       ((equal len 1)
352	(return (mapcar #'(lambda (*y*) (cons *y* nil)) f)))
353       ((null r) (return nil))
354       (t
355	(mapc #'(lambda (*y*)
356		  (setq ss
357			(nconc ss
358			       (mapcar #'(lambda (z) (cons z *y*))
359				       f))))
360	      (al1 (car r) (cdr r) (1- len)))
361	(return ss)))))
362
363
364(defun ap1 (x l)
365  (cond ((null l) nil)
366	(t (cons (ptimes x (car l)) (ap1 x (cdr l))))))
367
368(defun ptts1 (x n y)
369  (cond ((equal n 1) (list y))
370	(t (cons y (ptts1 x (1- n) (ptimes x y))))))
371
372(defun p1 (l)
373  (prog (a)
374     (setq a (mapcar #'p11 l))
375     (return (cond ((null l) nil)
376		   (t (cdr (al1 (car a)
377				(cdr a)
378				(length a))))))))
379
380(defun p11 (ele)
381  (cond ((null (cddr ele)) (rpowerset (car ele) (cadr ele)))
382	(t (allprods (rpowerset (car ele) (cadr ele))
383		     (p11 (cddr ele))))))
384
385(defun pinterpolate (l var)
386  (psimp var (pinterpolate1 (pinterpolate2 l 1)
387			    (- (length l) 2))))
388
389(defun pinterpolate1 (x n)
390  (pinterpolate4 (pinterpolate5 (reverse x) 1 n n) (1+ n)))
391
392(defun pinterpolate2 (x n)
393  (cond ((null (cdr x)) x)
394	(t (cons (car x)
395		 (pinterpolate2 (pinterpolate3 x n) (1+ n))))))
396
397(defun pinterpolate3 (x n)
398  (cond ((null (cdr x)) nil)
399	(t (cons (pquotient (pdifference (cadr x) (car x)) n)
400		 (pinterpolate3 (cdr x) n)))))
401
402(defun pinterpolate4 (x n)
403  (cond ((null x) nil)
404	((pzerop (car x)) (pinterpolate4 (cdr x) (1- n)))
405	(t (cons n (cons (car x)
406			 (pinterpolate4 (cdr x) (1- n)))))))
407
408(defun pinterpolate5 (x i j n)
409  (cond ((> i n) x)
410	(t (pinterpolate5 (cons (car x) (pinterpolate6 x i j))
411			  (1+ i)
412			  (1- j)
413			  n))))
414
415(defun pinterpolate6 (x i j)
416  (cond ((zerop i) (cdr x))
417	(t (cons (pdifference (cadr x) (pctimes j (car x)))
418		 (pinterpolate6 (cdr x) (1- i) j)))))
419
420;; THE N**(1.585) MULTIPLICATION SCHEME
421;;FOLLOWS.  IT SHOULD BE USED ONLY WHEN BOTH INPUTS ARE MULTIVARIATE,
422;;DENSE, AND OF NEARLY THE SAME SIZE.  OR ABSOLUTELY TREMENDOUS.
423;;(THE CLASSICAL MULTIPLICATION SCHEME IS N**2 WHERE N IS SIZE OF
424;;POLYNOMIAL   (OR N*M FOR DIFFERENT SIZES).  FOR THIS
425;;CASE, N IS APPX. THE SIZE OF LARGER.
426
427(defmfun $fasttimes (x y)
428  (cond ((and (not (atom x)) (not (atom y))
429	      (equal (car x) (car y)) (equal (caar x) 'mrat)
430	      (equal (cddr x) 1) (equal (cddr y) 1))
431	 (cons (car x)(cons (fptimes (cadr x)(cadr y))1)))
432	(t (merror (intl:gettext "fasttimes: arguments must be CRE polynomials with same variables.")))))
433
434(defun fptimes (x y)
435  (cond ((or (pzerop x) (pzerop y)) (pzero))
436	((pcoefp x) (pctimes x y))
437	((pcoefp y) (pctimes y x))
438	((eq (car x) (car y))
439	 (cond((or(univar(cdr x))(univar(cdr y)))
440	       (cons (car x) (ptimes1 (cdr x) (cdr y))))
441	      (t(cons (car x) (fptimes1 (cdr x)(cdr y))))))
442	((pointergp (car x) (car y))
443	 (cons (car x) (pctimes1 y (cdr x))))
444	(t (cons (car y) (pctimes1 x (cdr y))))))
445
446(defun fptimes1 (f g)
447  (prog (a b c d)
448     (cond ((or (null f) (null g)) (return nil))
449	   ((null (cddr f))
450	    (return (lsft (pctimes1 (cadr f) g) (car f))))
451	   ((null (cddr g))
452	    (return (lsft (pctimes1 (cadr g) f) (car g)))))
453     (setq d (ash (1+ (max (car f) (car g))) -1))
454     (setq f (halfsplit f d) g (halfsplit g d))
455     (setq a (fptimes1 (car f) (car g)))
456     (setq b
457	   (fptimes1 (ptptplus (car f) (cdr f)) (ptptplus (car g) (cdr g))))
458     (setq c (fptimes1 (cdr f) (cdr g)))
459     (setq b (ptptdiffer (ptptdiffer b a) c))
460     (return (ptptplus (lsft a (ash d 1)) (ptptplus (lsft b d) c)))))
461
462(defun halfsplit (p d)
463  (do ((a) (p p (cddr p)))
464      ((or (null p) (< (car p) d)) (cons (nreverse a) p))
465    (setq a (cons (cadr p) (cons (- (car p) d) a)))))
466
467(defun lsft (p n)
468  (do ((q p (cddr (rplaca q (+ (car q) n)))))
469      ((null q)))
470  p)
471
472(declare-top (special wtsofar xweight $ratwtlvl v *x*))
473
474;;; TO TRUNCATE ON E, DO RATWEIGHT(E,1);
475;;;THEN DO RATWTLVL:N.  ALL POWERS >N GO TO 0.
476
477(defmfun $ratweight (&rest args)
478  (when (oddp (length args))
479    (merror (intl:gettext "ratweight: number of arguments must be a multiple of 2.")))
480  (do ((l args (cddr l)))
481      ((null l))
482    (rplacd (or (assoc (first l) *ratweights :test #'equal)
483		(car (push (list (first l)) *ratweights)))
484	    (second l)))
485  (setq $ratweights (cons '(mlist simp) (dot2l *ratweights)))
486  (if (null args)
487      $ratweights
488      (cons '(mlist) args)))
489
490(defun pweight (x)
491  (or (get x '$ratweight) 0))
492
493(defun wtptimes (x y wtsofar)
494  (cond ((or (pzerop x) (pzerop y) (> wtsofar $ratwtlvl))
495	 (pzero))
496	((pcoefp x) (wtpctimes x y))
497	((pcoefp y) (wtpctimes y x))
498	((eq (car x) (car y))
499	 (palgsimp (car x)
500		   (wtptimes1 (cdr x)
501			      (cdr y)
502			      (pweight (car x)))
503		   (alg x)))
504	((pointergp (car x) (car y))
505	 (psimp (car x)
506		(wtpctimes1 y (cdr x) (pweight (car x)))))
507	(t (psimp (car y)
508		  (wtpctimes1 x (cdr y) (pweight (car y)))))))
509
510(defun wtptimes1 (*x* y xweight)
511  (prog (u* v)
512     (declare (special v))
513     (setq v (setq u* (wtptimes2 y)))
514     a    (setq *x* (cddr *x*))
515     (cond ((null *x*) (return u*)))
516     (wtptimes3 y)
517     (go a)))
518
519
520(defun wtptimes2 (y)
521  (if (null y)
522      nil
523      (let ((ii (+ (* xweight (+ (car *x*) (car y))) wtsofar)))
524	(if (> ii $ratwtlvl)
525	    (wtptimes2 (cddr y))
526	    (pcoefadd (+ (car *x*) (car y))
527		      (wtptimes (cadr *x*) (cadr y) ii)
528		      (wtptimes2 (cddr y)))))))
529
530(defun wtptimes3 (y)
531  (prog ((e 0) u c)
532     (declare (special v))
533     a1   (cond ((null y) (return nil)))
534     (setq e (+ (car *x*) (car y)))
535     (setq c (wtptimes (cadr y) (cadr *x*) (+ wtsofar (* xweight e))))
536     (cond ((pzerop c) (setq y (cddr y)) (go a1))
537	   ((or (null v) (> e (car v))) (setq u* (setq v (ptptplus u* (list e c)))) (setq y (cddr y)) (go a1))
538	   ((equal e (car v))
539	    (setq c (pplus c (cadr v)))
540	    (cond ((pzerop c) (setq u* (setq v (ptptdiffer u* (list (car v) (cadr v)))))) (t (rplaca (cdr v) c)))
541	    (setq y (cddr y))
542	    (go a1)))
543     a    (cond ((and (cddr v) (> (caddr v) e)) (setq v (cddr v)) (go a)))
544     (setq u (cdr v))
545     b    (cond ((or (null (cdr u)) (< (cadr u) e)) (rplacd u (cons e (cons c (cdr u)))) (go e)))
546     (cond ((pzerop (setq c (pplus (caddr u) c))) (rplacd u (cdddr u)) (go d)) (t (rplaca (cddr u) c)))
547     e    (setq u (cddr u))
548     d    (setq y (cddr y))
549     (cond ((null y) (return nil))
550	   ((pzerop
551	     (setq c (wtptimes (cadr *x*) (cadr y)
552			       (+ wtsofar (* xweight
553					       (setq e (+ (car *x*) (car y))))))))
554	    (go d)))
555     c    (cond ((and (cdr u) (> (cadr u) e)) (setq u (cddr u)) (go c)))
556     (go b)))
557
558
559(defun wtpctimes (c p)
560  (cond ((pcoefp p) (ctimes c p))
561	(t (psimp (car p) (wtpctimes1 c (cdr p) (pweight (car p)))))))
562
563(defun wtpctimes1 (c x xwt)
564  (prog (cc)
565     (return
566       (cond ((null x) nil)
567	     (t (setq cc (wtptimes c
568				   (cadr x)
569				   (+ wtsofar (* xwt (car x)))))
570		(cond ((pzerop cc) (wtpctimes1 c (cddr x) xwt))
571		      (t (cons (car x)
572			       (cons cc
573				     (wtpctimes1 c
574						 (cddr x)
575						 xwt))))))))))
576
577(defun wtpexpt (x n)
578  (cond ((= n 0) 1)
579	((= n 1) x)
580	((evenp n)
581	 (let ((xn2 (wtpexpt x (/ n 2))))
582	   (wtptimes xn2 xn2 0)))
583	(t (wtptimes x (wtpexpt x (1- n)) 0))))
584
585(defmfun $horner (e &rest l)
586  (let (($ratfac nil)
587	(varlist (cdr $ratvars))
588	genvar
589	(x nil)
590	(arg1 (taychk2rat e)))
591    (cond ((mbagp arg1)
592	   (cons (car arg1)
593		 (mapcar #'(lambda (u) (apply '$horner (cons u l))) (cdr arg1))))
594	  (t
595	   (setq x (apply #'$rat (cons arg1 l)))
596	   (mapc #'(lambda (y z) (putprop y z 'disrep)) (cadddr (car x)) (caddar x))
597	   (div* (hornrep (cadr x)) (hornrep (cddr x)))))))
598
599(defun hornrep (p)
600  (if (pcoefp p)
601      p
602      (horn+ (cdr p) (get (car p) 'disrep))))
603
604(defun horn+ (l var)
605  (prog (ans last)
606     (setq ans (hornrep (cadr l)))
607     a (setq last (car l) l (cddr l))
608     (cond ((null l)
609	    (return (cond ((equal last 0) ans)
610			  (t (list '(mtimes)
611				   (list '(mexpt) var last) ans)))))
612	   (t (setq ans (list '(mplus)
613			      (hornrep (cadr l))
614			      (list '(mtimes)
615				    (list '(mexpt) var (- last (car l)))
616				    ans)))))
617     (go a)))
618
619(declare-top (special y genvar $savefactors checkfactors
620		      exp var x $factorflag $ratfac
621		      ratform
622		      wholepart parnumer varlist n))
623
624(defmfun $partfrac (exp var)
625  (cond ((mbagp exp)
626	 (cons (car exp) (mapcar #'(lambda (u) ($partfrac u var)) (cdr exp))))
627	((and (atom var) (not (among var exp))) exp)
628	(t (let (($savefactors t) (checkfactors ()) (varlist (list var))
629		 $ratfac $algebraic $keepfloat ratform genvar)
630	     (desetq (ratform . exp) (taychk2rat exp))
631	     (setq var (caadr (ratf var)))
632	     (setq exp (partfrac exp var))
633	     (setq exp (cons (car exp)	;FULL DECOMP?
634			     (mapcan #'partfraca (cdr exp))))
635	     (add2* (disrep (car exp))
636		    (cons '(mplus)
637			  (mapcar #'(lambda (l)
638				      (destructuring-let (((coef poly exp) l))
639							 (list '(mtimes)
640							       (disrep  coef)
641							       (list '(mexpt)
642								     (disrep poly)
643								     (- exp)))))
644				  (cdr exp))))))))
645
646(defun partfraca (llist)
647  (destructuring-let (((coef poly exp) llist))
648    (do ((nc (ratdivide coef poly) (ratdivide (car nc) poly))
649	 (n exp (1- n))
650	 (ans))
651	((rzerop (car nc)) (cons (list (cdr nc) poly n) ans))
652      (push (list (cdr nc) poly n) ans))))
653
654(defun partfrac (rat var)
655  (destructuring-let* (((wholepart frpart) (pdivide (car rat) (cdr rat)))
656		       ((num . denom) (ratqu frpart (cdr rat))))
657    (cond
658      ((pzerop num) (cons wholepart nil))
659      ((or (pcoefp denom) (pointergp var (car denom))) (cons rat nil))
660      (t (destructuring-let (((content bpart) (oldcontent denom)))
661           (let (apart y parnumer)
662             (loop
663               for (factor multiplicity)
664                 on (pfactor bpart) by #'cddr
665               unless (zerop (pdegree factor var))
666                 do
667                    (setq apart (pexpt factor multiplicity)
668                          bpart (pquotient bpart apart)
669                          y (bprog apart bpart)
670                          frpart (cdr (ratdivide (ratti num (cdr y) t)
671                                                 apart)))
672                    (push (list (ratqu frpart content) factor multiplicity)
673                          parnumer)
674                    (desetq (num . content)
675                            (cdr (ratdivide (ratqu (ratti num (car y) t)
676                                                   content)
677                                            bpart))))
678             (cons wholepart parnumer)))))))
679
680(declare-top (unspecial exp f n ss v var xv y *chk *l *max *p
681			*res u* *x* *y*))
682
683;; $RATDIFF TAKES DERIVATIVES FAST.  IT ASSUMES THAT THE
684;; ONLY ENTITY WHICH DEPENDS ON X IS X ITSELF.
685;; THAT IS, DEPENDENCIES DECLARED EXPLICITLY OR IMPLICITLY ARE
686;; TOTALLY IGNORED.  RATDIFF(F(X),X) IS 0.  RATDIFF(Y,X) IS 0.
687;; ANY OTHER USAGE MUST GO THROUGH $DIFF.
688;; FURTHERMORE, X IS ASSUMED TO BE AN ATOM OR A SINGLE ITEM ON
689;; VARLIST.  E.G. X MIGHT BE SIN(U), BUT NOT 2*SIN(U).
690
691(declare-top (special varlist genvar x))
692
693(defmfun $ratdiff (p x)
694  (if ($ratp p)
695      (setq p (minimize-varlist
696	       (if (member 'trunc (cdar p) :test #'eq) ($taytorat p) p))))
697  (let ((formflag ($ratp p)) (varlist) (genvar))
698    (newvar x) (newvar p)
699    (or (every #'(lambda (exp)
700		     (or (alike1 x exp) (free exp x)))
701		 varlist)
702	(merror (intl:gettext "ratdiff: first argument must be a polynomial in ~M; found: ~M") x p))
703    (setq p (ratf p))
704    (setq x (caadr (ratf x)))
705    (setq p (cons (car p) (ratderivative (cdr p) x)))
706    (if formflag p ($ratdisrep p))))
707
708(declare-top (unspecial x))
709
710(declare-top (special $pfeformat varlist $factorflag m v dosimp))
711
712(defmfun $pfet (m)
713  (prog (listov $pfeformat varlist $factorflag)
714     (setq $pfeformat t)
715     (newvar m)
716     (setq listov varlist)
717     (mapc #'(lambda (r) (setq m (pfet1 m r)))
718	   listov)
719     (setq m (simplify m))
720     (setq m (cond ((atom m) m)
721		   ((eq (caar m) 'mplus)
722		    (cons '(mplus)
723			  (mapcar #'$ratexpand (cdr m))))
724		   (t ($ratexpand m))))
725     (return (cond ((atom m) m)
726		   ((eq (caar m) 'mplus)
727		    (cons '(mplus)
728			  (mapcar #'sssqfr (cdr m))))
729		   (t (sssqfr m))))))
730
731(defun sssqfr (x)
732  (let ((dosimp t)) (simplify ($sqfr x))))
733
734(defun pfet1 (m v)
735  (cond ((atom m) m)
736	((eq (caar m) 'mplus)
737	 (cons '(mplus)
738	       (mapcar #'(lambda (s) ($partfrac s v))
739		       (cdr m))))
740	(t ($partfrac m v))))
741
742(declare-top (unspecial m v))
743