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1;;; calcalg3.el --- more algebraic functions for Calc
2
bf77c646 3;; Copyright (C) 1990, 1991, 1992, 1993, 2001 Free Software Foundation, Inc.
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4
5;; Author: David Gillespie <daveg@synaptics.com>
a1506d29 6;; Maintainers: D. Goel <deego@gnufans.org>
6e1c888a 7;; Colin Walters <walters@debian.org>
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8
9;; This file is part of GNU Emacs.
10
11;; GNU Emacs is distributed in the hope that it will be useful,
12;; but WITHOUT ANY WARRANTY. No author or distributor
13;; accepts responsibility to anyone for the consequences of using it
14;; or for whether it serves any particular purpose or works at all,
15;; unless he says so in writing. Refer to the GNU Emacs General Public
16;; License for full details.
17
18;; Everyone is granted permission to copy, modify and redistribute
19;; GNU Emacs, but only under the conditions described in the
20;; GNU Emacs General Public License. A copy of this license is
21;; supposed to have been given to you along with GNU Emacs so you
22;; can know your rights and responsibilities. It should be in a
23;; file named COPYING. Among other things, the copyright notice
24;; and this notice must be preserved on all copies.
25
3132f345 26;;; Commentary:
136211a9 27
3132f345 28;;; Code:
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29
30;; This file is autoloaded from calc-ext.el.
31(require 'calc-ext)
32
33(require 'calc-macs)
34
35(defun calc-Need-calc-alg-3 () nil)
36
37
38(defun calc-find-root (var)
39 (interactive "sVariable(s) to solve for: ")
40 (calc-slow-wrapper
41 (let ((func (if (calc-is-hyperbolic) 'calcFunc-wroot 'calcFunc-root)))
42 (if (or (equal var "") (equal var "$"))
43 (calc-enter-result 2 "root" (list func
44 (calc-top-n 3)
45 (calc-top-n 1)
46 (calc-top-n 2)))
47 (let ((var (if (and (string-match ",\\|[^ ] +[^ ]" var)
48 (not (string-match "\\[" var)))
49 (math-read-expr (concat "[" var "]"))
50 (math-read-expr var))))
51 (if (eq (car-safe var) 'error)
52 (error "Bad format in expression: %s" (nth 1 var)))
53 (calc-enter-result 1 "root" (list func
54 (calc-top-n 2)
55 var
bf77c646 56 (calc-top-n 1))))))))
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57
58(defun calc-find-minimum (var)
59 (interactive "sVariable(s) to minimize over: ")
60 (calc-slow-wrapper
61 (let ((func (if (calc-is-inverse)
62 (if (calc-is-hyperbolic)
63 'calcFunc-wmaximize 'calcFunc-maximize)
64 (if (calc-is-hyperbolic)
65 'calcFunc-wminimize 'calcFunc-minimize)))
66 (tag (if (calc-is-inverse) "max" "min")))
67 (if (or (equal var "") (equal var "$"))
68 (calc-enter-result 2 tag (list func
69 (calc-top-n 3)
70 (calc-top-n 1)
71 (calc-top-n 2)))
72 (let ((var (if (and (string-match ",\\|[^ ] +[^ ]" var)
73 (not (string-match "\\[" var)))
74 (math-read-expr (concat "[" var "]"))
75 (math-read-expr var))))
76 (if (eq (car-safe var) 'error)
77 (error "Bad format in expression: %s" (nth 1 var)))
78 (calc-enter-result 1 tag (list func
79 (calc-top-n 2)
80 var
bf77c646 81 (calc-top-n 1))))))))
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82
83(defun calc-find-maximum (var)
84 (interactive "sVariable to maximize over: ")
85 (calc-invert-func)
bf77c646 86 (calc-find-minimum var))
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87
88
89(defun calc-poly-interp (arg)
90 (interactive "P")
91 (calc-slow-wrapper
92 (let ((data (calc-top 2)))
93 (if (or (consp arg) (eq arg 0) (eq arg 2))
94 (setq data (cons 'vec (calc-top-list 2 2)))
95 (or (null arg)
96 (error "Bad prefix argument")))
97 (if (calc-is-hyperbolic)
98 (calc-enter-result 1 "rati" (list 'calcFunc-ratint data (calc-top 1)))
99 (calc-enter-result 1 "poli" (list 'calcFunc-polint data
bf77c646 100 (calc-top 1)))))))
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101
102
103(defun calc-curve-fit (arg &optional model coefnames varnames)
104 (interactive "P")
105 (calc-slow-wrapper
106 (setq calc-aborted-prefix nil)
107 (let ((func (if (calc-is-inverse) 'calcFunc-xfit
108 (if (calc-is-hyperbolic) 'calcFunc-efit
109 'calcFunc-fit)))
110 key (which 0)
111 n nvars temp data
112 (homog nil)
113 (msgs '( "(Press ? for help)"
114 "1 = linear or multilinear"
115 "2-9 = polynomial fits; i = interpolating polynomial"
116 "p = a x^b, ^ = a b^x"
117 "e = a exp(b x), x = exp(a + b x), l = a + b ln(x)"
118 "E = a 10^(b x), X = 10^(a + b x), L = a + b log10(x)"
119 "q = a + b (x-c)^2"
120 "g = (a/b sqrt(2 pi)) exp(-0.5*((x-c)/b)^2)"
121 "h prefix = homogeneous model (no constant term)"
122 "' = alg entry, $ = stack, u = Model1, U = Model2")))
123 (while (not model)
124 (message "Fit to model: %s:%s"
125 (nth which msgs)
126 (if homog " h" ""))
127 (setq key (read-char))
128 (cond ((= key ?\C-g)
129 (keyboard-quit))
130 ((= key ??)
131 (setq which (% (1+ which) (length msgs))))
132 ((memq key '(?h ?H))
133 (setq homog (not homog)))
134 ((progn
135 (if (eq key ?\$)
136 (setq n 1)
137 (setq n 0))
138 (cond ((null arg)
139 (setq n (1+ n)
140 data (calc-top n)))
141 ((or (consp arg) (eq arg 0))
142 (setq n (+ n 2)
143 data (calc-top n)
144 data (if (math-matrixp data)
145 (append data (list (calc-top (1- n))))
146 (list 'vec data (calc-top (1- n))))))
147 ((> (setq arg (prefix-numeric-value arg)) 0)
148 (setq data (cons 'vec (calc-top-list arg (1+ n)))
149 n (+ n arg)))
150 (t (error "Bad prefix argument")))
151 (or (math-matrixp data) (not (cdr (cdr data)))
152 (error "Data matrix is not a matrix!"))
153 (setq nvars (- (length data) 2)
154 coefnames nil
155 varnames nil)
156 nil))
157 ((= key ?1) ; linear or multilinear
158 (calc-get-fit-variables nvars (1+ nvars) (and homog 0))
159 (setq model (math-mul coefnames
160 (cons 'vec (cons 1 (cdr varnames))))))
161 ((and (>= key ?2) (<= key ?9)) ; polynomial
162 (calc-get-fit-variables 1 (- key ?0 -1) (and homog 0))
163 (setq model (math-build-polynomial-expr (cdr coefnames)
164 (nth 1 varnames))))
165 ((= key ?i) ; exact polynomial
166 (calc-get-fit-variables 1 (1- (length (nth 1 data)))
167 (and homog 0))
168 (setq model (math-build-polynomial-expr (cdr coefnames)
169 (nth 1 varnames))))
170 ((= key ?p) ; power law
171 (calc-get-fit-variables nvars (1+ nvars) (and homog 1))
172 (setq model (math-mul (nth 1 coefnames)
173 (calcFunc-reduce
174 '(var mul var-mul)
175 (calcFunc-map
176 '(var pow var-pow)
177 varnames
178 (cons 'vec (cdr (cdr coefnames))))))))
179 ((= key ?^) ; exponential law
180 (calc-get-fit-variables nvars (1+ nvars) (and homog 1))
181 (setq model (math-mul (nth 1 coefnames)
182 (calcFunc-reduce
183 '(var mul var-mul)
184 (calcFunc-map
185 '(var pow var-pow)
186 (cons 'vec (cdr (cdr coefnames)))
187 varnames)))))
188 ((memq key '(?e ?E))
189 (calc-get-fit-variables nvars (1+ nvars) (and homog 1))
190 (setq model (math-mul (nth 1 coefnames)
191 (calcFunc-reduce
192 '(var mul var-mul)
193 (calcFunc-map
194 (if (eq key ?e)
195 '(var exp var-exp)
196 '(calcFunc-lambda
197 (var a var-a)
198 (^ 10 (var a var-a))))
199 (calcFunc-map
200 '(var mul var-mul)
201 (cons 'vec (cdr (cdr coefnames)))
202 varnames))))))
203 ((memq key '(?x ?X))
204 (calc-get-fit-variables nvars (1+ nvars) (and homog 0))
205 (setq model (math-mul coefnames
206 (cons 'vec (cons 1 (cdr varnames)))))
207 (setq model (if (eq key ?x)
208 (list 'calcFunc-exp model)
209 (list '^ 10 model))))
210 ((memq key '(?l ?L))
211 (calc-get-fit-variables nvars (1+ nvars) (and homog 0))
212 (setq model (math-mul coefnames
213 (cons 'vec
214 (cons 1 (cdr (calcFunc-map
215 (if (eq key ?l)
216 '(var ln var-ln)
217 '(var log10
218 var-log10))
219 varnames)))))))
220 ((= key ?q)
221 (calc-get-fit-variables nvars (1+ (* 2 nvars)) (and homog 0))
222 (let ((c coefnames)
223 (v varnames))
224 (setq model (nth 1 c))
225 (while (setq v (cdr v) c (cdr (cdr c)))
226 (setq model (math-add
227 model
228 (list '*
229 (car c)
230 (list '^
231 (list '- (car v) (nth 1 c))
232 2)))))))
233 ((= key ?g)
234 (setq model (math-read-expr "(AFit / BFit sqrt(2 pi)) exp(-0.5 * ((XFit - CFit) / BFit)^2)")
235 varnames '(vec (var XFit var-XFit))
236 coefnames '(vec (var AFit var-AFit)
237 (var BFit var-BFit)
238 (var CFit var-CFit)))
239 (calc-get-fit-variables 1 (1- (length coefnames)) (and homog 1)))
240 ((memq key '(?\$ ?\' ?u ?U))
241 (let* ((defvars nil)
242 (record-entry nil))
243 (if (eq key ?\')
244 (let* ((calc-dollar-values calc-arg-values)
245 (calc-dollar-used 0)
246 (calc-hashes-used 0))
247 (setq model (calc-do-alg-entry "" "Model formula: "))
248 (if (/= (length model) 1)
249 (error "Bad format"))
250 (setq model (car model)
251 record-entry t)
252 (if (> calc-dollar-used 0)
253 (setq coefnames
254 (cons 'vec
255 (nthcdr (- (length calc-arg-values)
256 calc-dollar-used)
257 (reverse calc-arg-values))))
258 (if (> calc-hashes-used 0)
259 (setq coefnames
260 (cons 'vec (calc-invent-args
261 calc-hashes-used))))))
262 (progn
263 (setq model (cond ((eq key ?u)
264 (calc-var-value 'var-Model1))
265 ((eq key ?U)
266 (calc-var-value 'var-Model2))
267 (t (calc-top 1))))
268 (or model (error "User model not yet defined"))
269 (if (math-vectorp model)
270 (if (and (memq (length model) '(3 4))
271 (not (math-objvecp (nth 1 model)))
272 (math-vectorp (nth 2 model))
273 (or (null (nth 3 model))
274 (math-vectorp (nth 3 model))))
275 (setq varnames (nth 2 model)
276 coefnames (or (nth 3 model)
277 (cons 'vec
278 (math-all-vars-but
279 model varnames)))
280 model (nth 1 model))
281 (error "Incorrect model specifier")))))
282 (or varnames
283 (let ((with-y (eq (car-safe model) 'calcFunc-eq)))
284 (if coefnames
285 (calc-get-fit-variables (if with-y (1+ nvars) nvars)
286 (1- (length coefnames))
287 (math-all-vars-but
288 model coefnames)
289 nil with-y)
290 (let* ((coefs (math-all-vars-but model nil))
291 (vars nil)
292 (n (- (length coefs) nvars (if with-y 2 1)))
293 p)
294 (if (< n 0)
295 (error "Not enough variables in model"))
296 (setq p (nthcdr n coefs))
297 (setq vars (cdr p))
298 (setcdr p nil)
299 (calc-get-fit-variables (if with-y (1+ nvars) nvars)
300 (length coefs)
301 vars coefs with-y)))))
302 (if record-entry
303 (calc-record (list 'vec model varnames coefnames)
304 "modl"))))
305 (t (beep))))
306 (let ((calc-fit-to-trail t))
307 (calc-enter-result n (substring (symbol-name func) 9)
308 (list func model
309 (if (= (length varnames) 2)
310 (nth 1 varnames)
311 varnames)
312 (if (= (length coefnames) 2)
313 (nth 1 coefnames)
314 coefnames)
315 data))
316 (if (consp calc-fit-to-trail)
bf77c646 317 (calc-record (calc-normalize calc-fit-to-trail) "parm"))))))
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318
319(defun calc-invent-independent-variables (n &optional but)
bf77c646 320 (calc-invent-variables n but '(x y z t) "x"))
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321
322(defun calc-invent-parameter-variables (n &optional but)
bf77c646 323 (calc-invent-variables n but '(a b c d) "a"))
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324
325(defun calc-invent-variables (num but names base)
326 (let ((vars nil)
327 (n num) (nn 0)
328 var)
329 (while (and (> n 0) names)
330 (setq var (math-build-var-name (if (consp names)
331 (car names)
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332 (concat base (int-to-string
333 (setq nn (1+ nn)))))))
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334 (or (math-expr-contains (cons 'vec but) var)
335 (setq vars (cons var vars)
336 n (1- n)))
337 (or (symbolp names) (setq names (cdr names))))
338 (if (= n 0)
339 (nreverse vars)
bf77c646 340 (calc-invent-variables num but t base))))
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341
342(defun calc-get-fit-variables (nv nc &optional defv defc with-y homog)
343 (or (= nv (if with-y (1+ nvars) nvars))
344 (error "Wrong number of data vectors for this type of model"))
345 (if (integerp defv)
346 (setq homog defv
347 defv nil))
348 (if homog
349 (setq nc (1- nc)))
350 (or defv
351 (setq defv (calc-invent-independent-variables nv)))
352 (or defc
353 (setq defc (calc-invent-parameter-variables nc defv)))
354 (let ((vars (read-string (format "Fitting variables: (default %s; %s) "
355 (mapconcat 'symbol-name
356 (mapcar (function (lambda (v)
357 (nth 1 v)))
358 defv)
359 ",")
360 (mapconcat 'symbol-name
361 (mapcar (function (lambda (v)
362 (nth 1 v)))
363 defc)
364 ","))))
365 (coefs nil))
366 (setq vars (if (string-match "\\[" vars)
367 (math-read-expr vars)
368 (math-read-expr (concat "[" vars "]"))))
369 (if (eq (car-safe vars) 'error)
370 (error "Bad format in expression: %s" (nth 2 vars)))
371 (or (math-vectorp vars)
372 (error "Expected a variable or vector of variables"))
373 (if (equal vars '(vec))
374 (setq vars (cons 'vec defv)
375 coefs (cons 'vec defc))
376 (if (math-vectorp (nth 1 vars))
377 (if (and (= (length vars) 3)
378 (math-vectorp (nth 2 vars)))
379 (setq coefs (nth 2 vars)
380 vars (nth 1 vars))
381 (error
382 "Expected independent variables vector, then parameters vector"))
383 (setq coefs (cons 'vec defc))))
384 (or (= nv (1- (length vars)))
385 (and (not with-y) (= (1+ nv) (1- (length vars))))
386 (error "Expected %d independent variable%s" nv (if (= nv 1) "" "s")))
387 (or (= nc (1- (length coefs)))
388 (error "Expected %d parameter variable%s" nc (if (= nc 1) "" "s")))
389 (if homog
390 (setq coefs (cons 'vec (cons homog (cdr coefs)))))
391 (if varnames
392 (setq model (math-multi-subst model (cdr varnames) (cdr vars))))
393 (if coefnames
394 (setq model (math-multi-subst model (cdr coefnames) (cdr coefs))))
395 (setq varnames vars
bf77c646 396 coefnames coefs)))
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397
398
399
400
401;;; The following algorithms are from Numerical Recipes chapter 9.
402
403;;; "rtnewt" with safety kludges
404(defun math-newton-root (expr deriv guess orig-guess limit)
405 (math-working "newton" guess)
406 (let* ((var-DUMMY guess)
407 next dval)
408 (setq next (math-evaluate-expr expr)
409 dval (math-evaluate-expr deriv))
410 (if (and (Math-numberp next)
411 (Math-numberp dval)
412 (not (Math-zerop dval)))
413 (progn
414 (setq next (math-sub guess (math-div next dval)))
415 (if (math-nearly-equal guess (setq next (math-float next)))
416 (progn
417 (setq var-DUMMY next)
418 (list 'vec next (math-evaluate-expr expr)))
419 (if (Math-lessp (math-abs-approx (math-sub next orig-guess))
420 limit)
421 (math-newton-root expr deriv next orig-guess limit)
422 (math-reject-arg next "*Newton's method failed to converge"))))
bf77c646 423 (math-reject-arg next "*Newton's method encountered a singularity"))))
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424
425;;; Inspired by "rtsafe"
426(defun math-newton-search-root (expr deriv guess vguess ostep oostep
427 low vlow high vhigh)
428 (let ((var-DUMMY guess)
429 (better t)
430 pos step next vnext)
431 (if guess
432 (math-working "newton" (list 'intv 0 low high))
433 (math-working "bisect" (list 'intv 0 low high))
434 (setq ostep (math-mul-float (math-sub-float high low)
435 '(float 5 -1))
436 guess (math-add-float low ostep)
437 var-DUMMY guess
438 vguess (math-evaluate-expr expr))
439 (or (Math-realp vguess)
440 (progn
441 (setq ostep (math-mul-float ostep '(float 6 -1))
442 guess (math-add-float low ostep)
443 var-DUMMY guess
444 vguess (math-evaluate-expr expr))
445 (or (math-realp vguess)
446 (progn
447 (setq ostep (math-mul-float ostep '(float 123456 -5))
448 guess (math-add-float low ostep)
449 var-DUMMY guess
450 vguess nil))))))
451 (or vguess
452 (setq vguess (math-evaluate-expr expr)))
453 (or (Math-realp vguess)
454 (math-reject-arg guess "*Newton's method encountered a singularity"))
455 (setq vguess (math-float vguess))
456 (if (eq (Math-negp vlow) (setq pos (Math-posp vguess)))
457 (setq high guess
458 vhigh vguess)
459 (if (eq (Math-negp vhigh) pos)
460 (setq low guess
461 vlow vguess)
462 (setq better nil)))
463 (if (or (Math-zerop vguess)
464 (math-nearly-equal low high))
465 (list 'vec guess vguess)
466 (setq step (math-evaluate-expr deriv))
467 (if (and (Math-realp step)
468 (not (Math-zerop step))
469 (setq step (math-div-float vguess (math-float step))
470 next (math-sub-float guess step))
471 (not (math-lessp-float high next))
472 (not (math-lessp-float next low)))
473 (progn
474 (setq var-DUMMY next
475 vnext (math-evaluate-expr expr))
476 (if (or (Math-zerop vnext)
477 (math-nearly-equal next guess))
478 (list 'vec next vnext)
479 (if (and better
480 (math-lessp-float (math-abs (or oostep
481 (math-sub-float
482 high low)))
483 (math-abs
484 (math-mul-float '(float 2 0)
485 step))))
486 (math-newton-search-root expr deriv nil nil nil ostep
487 low vlow high vhigh)
488 (math-newton-search-root expr deriv next vnext step ostep
489 low vlow high vhigh))))
490 (if (or (and (Math-posp vlow) (Math-posp vhigh))
491 (and (Math-negp vlow) (Math-negp vhigh)))
492 (math-search-root expr deriv low vlow high vhigh)
493 (math-newton-search-root expr deriv nil nil nil ostep
bf77c646 494 low vlow high vhigh))))))
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495
496;;; Search for a root in an interval with no overt zero crossing.
497(defun math-search-root (expr deriv low vlow high vhigh)
498 (let (found)
499 (if root-widen
500 (let ((iters 0)
501 (iterlim (if (eq root-widen 'point)
502 (+ calc-internal-prec 10)
503 20))
504 (factor (if (eq root-widen 'point)
505 '(float 9 0)
506 '(float 16 -1)))
507 (prev nil) vprev waslow
508 diff)
509 (while (or (and (math-posp vlow) (math-posp vhigh))
510 (and (math-negp vlow) (math-negp vhigh)))
511 (math-working "widen" (list 'intv 0 low high))
512 (if (> (setq iters (1+ iters)) iterlim)
513 (math-reject-arg (list 'intv 0 low high)
514 "*Unable to bracket root"))
515 (if (= iters calc-internal-prec)
516 (setq factor '(float 16 -1)))
517 (setq diff (math-mul-float (math-sub-float high low) factor))
518 (if (Math-zerop diff)
519 (setq high (calcFunc-incr high 10))
520 (if (math-lessp-float (math-abs vlow) (math-abs vhigh))
521 (setq waslow t
522 prev low
523 low (math-sub low diff)
524 var-DUMMY low
525 vprev vlow
526 vlow (math-evaluate-expr expr))
527 (setq waslow nil
528 prev high
529 high (math-add high diff)
530 var-DUMMY high
531 vprev vhigh
532 vhigh (math-evaluate-expr expr)))))
533 (if prev
534 (if waslow
535 (setq high prev vhigh vprev)
536 (setq low prev vlow vprev)))
537 (setq found t))
538 (or (Math-realp vlow)
539 (math-reject-arg vlow 'realp))
540 (or (Math-realp vhigh)
541 (math-reject-arg vhigh 'realp))
542 (let ((xvals (list low high))
543 (yvals (list vlow vhigh))
544 (pos (Math-posp vlow))
545 (levels 0)
546 (step (math-sub-float high low))
547 xp yp var-DUMMY)
548 (while (and (<= (setq levels (1+ levels)) 5)
549 (not found))
550 (setq xp xvals
551 yp yvals
552 step (math-mul-float step '(float 497 -3)))
553 (while (and (cdr xp) (not found))
554 (if (Math-realp (car yp))
555 (setq low (car xp)
556 vlow (car yp)))
557 (setq high (math-add-float (car xp) step)
558 var-DUMMY high
559 vhigh (math-evaluate-expr expr))
560 (math-working "search" high)
561 (if (and (Math-realp vhigh)
562 (eq (math-negp vhigh) pos))
563 (setq found t)
564 (setcdr xp (cons high (cdr xp)))
565 (setcdr yp (cons vhigh (cdr yp)))
566 (setq xp (cdr (cdr xp))
567 yp (cdr (cdr yp))))))))
568 (if found
569 (if (Math-zerop vhigh)
570 (list 'vec high vhigh)
571 (if (Math-zerop vlow)
572 (list 'vec low vlow)
573 (if deriv
574 (math-newton-search-root expr deriv nil nil nil nil
575 low vlow high vhigh)
576 (math-bisect-root expr low vlow high vhigh))))
577 (math-reject-arg (list 'intv 3 low high)
bf77c646 578 "*Unable to find a sign change in this interval"))))
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579
580;;; "rtbis" (but we should be using Brent's method)
581(defun math-bisect-root (expr low vlow high vhigh)
582 (let ((step (math-sub-float high low))
583 (pos (Math-posp vhigh))
584 var-DUMMY
585 mid vmid)
586 (while (not (or (math-nearly-equal low
587 (setq step (math-mul-float
588 step '(float 5 -1))
589 mid (math-add-float low step)))
590 (progn
591 (setq var-DUMMY mid
592 vmid (math-evaluate-expr expr))
593 (Math-zerop vmid))))
594 (math-working "bisect" mid)
595 (if (eq (Math-posp vmid) pos)
596 (setq high mid
597 vhigh vmid)
598 (setq low mid
599 vlow vmid)))
bf77c646 600 (list 'vec mid vmid)))
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601
602;;; "mnewt"
603(defun math-newton-multi (expr jacob n guess orig-guess limit)
604 (let ((m -1)
605 (p guess)
606 p2 expr-val jacob-val next)
607 (while (< (setq p (cdr p) m (1+ m)) n)
608 (set (nth 2 (aref math-root-vars m)) (car p)))
609 (setq expr-val (math-evaluate-expr expr)
610 jacob-val (math-evaluate-expr jacob))
3132f345
CW
611 (unless (and (math-constp expr-val)
612 (math-constp jacob-val))
613 (math-reject-arg guess "*Newton's method encountered a singularity"))
136211a9
EZ
614 (setq next (math-add guess (math-div (math-float (math-neg expr-val))
615 (math-float jacob-val)))
616 p guess p2 next)
617 (math-working "newton" next)
618 (while (and (setq p (cdr p) p2 (cdr p2))
619 (math-nearly-equal (car p) (car p2))))
620 (if p
621 (if (Math-lessp (math-abs-approx (math-sub next orig-guess))
622 limit)
623 (math-newton-multi expr jacob n next orig-guess limit)
624 (math-reject-arg nil "*Newton's method failed to converge"))
bf77c646 625 (list 'vec next expr-val))))
136211a9
EZ
626
627(defvar math-root-vars [(var DUMMY var-DUMMY)])
628
629(defun math-find-root (expr var guess root-widen)
630 (if (eq (car-safe expr) 'vec)
631 (let ((n (1- (length expr)))
632 (calc-symbolic-mode nil)
633 (var-DUMMY nil)
634 (jacob (list 'vec))
635 p p2 m row)
3132f345
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636 (unless (eq (car-safe var) 'vec)
637 (math-reject-arg var 'vectorp))
638 (unless (= (length var) (1+ n))
639 (math-dimension-error))
136211a9
EZ
640 (setq expr (copy-sequence expr))
641 (while (>= n (length math-root-vars))
642 (let ((symb (intern (concat "math-root-v"
643 (int-to-string
644 (length math-root-vars))))))
645 (setq math-root-vars (vconcat math-root-vars
646 (vector (list 'var symb symb))))))
647 (setq m -1)
648 (while (< (setq m (1+ m)) n)
649 (set (nth 2 (aref math-root-vars m)) nil))
650 (setq m -1 p var)
651 (while (setq m (1+ m) p (cdr p))
652 (or (eq (car-safe (car p)) 'var)
653 (math-reject-arg var "*Expected a variable"))
654 (setq p2 expr)
655 (while (setq p2 (cdr p2))
656 (setcar p2 (math-expr-subst (car p2) (car p)
657 (aref math-root-vars m)))))
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658 (unless (eq (car-safe guess) 'vec)
659 (math-reject-arg guess 'vectorp))
660 (unless (= (length guess) (1+ n))
661 (math-dimension-error))
136211a9
EZ
662 (setq guess (copy-sequence guess)
663 p guess)
664 (while (setq p (cdr p))
665 (or (Math-numberp (car guess))
666 (math-reject-arg guess 'numberp))
667 (setcar p (math-float (car p))))
668 (setq p expr)
669 (while (setq p (cdr p))
670 (if (assq (car-safe (car p)) calc-tweak-eqn-table)
671 (setcar p (math-sub (nth 1 (car p)) (nth 2 (car p)))))
672 (setcar p (math-evaluate-expr (car p)))
673 (setq row (list 'vec)
674 m -1)
675 (while (< (setq m (1+ m)) n)
676 (nconc row (list (math-evaluate-expr
677 (or (calcFunc-deriv (car p)
678 (aref math-root-vars m)
679 nil t)
680 (math-reject-arg
681 expr
682 "*Formulas must be differentiable"))))))
683 (nconc jacob (list row)))
684 (setq m (math-abs-approx guess))
685 (math-newton-multi expr jacob n guess guess
686 (if (math-zerop m) '(float 1 3) (math-mul m 10))))
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687 (unless (eq (car-safe var) 'var)
688 (math-reject-arg var "*Expected a variable"))
689 (unless (math-expr-contains expr var)
690 (math-reject-arg expr "*Formula does not contain specified variable"))
136211a9
EZ
691 (if (assq (car expr) calc-tweak-eqn-table)
692 (setq expr (math-sub (nth 1 expr) (nth 2 expr))))
693 (math-with-extra-prec 2
694 (setq expr (math-expr-subst expr var '(var DUMMY var-DUMMY)))
695 (let* ((calc-symbolic-mode nil)
696 (var-DUMMY nil)
697 (expr (math-evaluate-expr expr))
698 (deriv (calcFunc-deriv expr '(var DUMMY var-DUMMY) nil t))
699 low high vlow vhigh)
700 (and deriv (setq deriv (math-evaluate-expr deriv)))
701 (setq guess (math-float guess))
702 (if (and (math-numberp guess)
703 deriv)
704 (math-newton-root expr deriv guess guess
705 (if (math-zerop guess) '(float 1 6)
706 (math-mul (math-abs-approx guess) 100)))
707 (if (Math-realp guess)
708 (setq low guess
709 high guess
710 var-DUMMY guess
711 vlow (math-evaluate-expr expr)
712 vhigh vlow
713 root-widen 'point)
714 (if (eq (car guess) 'intv)
715 (progn
716 (or (math-constp guess) (math-reject-arg guess 'constp))
717 (setq low (nth 2 guess)
718 high (nth 3 guess))
719 (if (memq (nth 1 guess) '(0 1))
720 (setq low (calcFunc-incr low 1 high)))
721 (if (memq (nth 1 guess) '(0 2))
722 (setq high (calcFunc-incr high -1 low)))
723 (setq var-DUMMY low
724 vlow (math-evaluate-expr expr)
725 var-DUMMY high
726 vhigh (math-evaluate-expr expr)))
727 (if (math-complexp guess)
728 (math-reject-arg "*Complex root finder must have derivative")
729 (math-reject-arg guess 'realp))))
730 (if (Math-zerop vlow)
731 (list 'vec low vlow)
732 (if (Math-zerop vhigh)
733 (list 'vec high vhigh)
734 (if (and deriv (Math-numberp vlow) (Math-numberp vhigh))
735 (math-newton-search-root expr deriv nil nil nil nil
736 low vlow high vhigh)
737 (if (or (and (Math-posp vlow) (Math-posp vhigh))
738 (and (Math-negp vlow) (Math-negp vhigh))
739 (not (Math-numberp vlow))
740 (not (Math-numberp vhigh)))
741 (math-search-root expr deriv low vlow high vhigh)
bf77c646 742 (math-bisect-root expr low vlow high vhigh))))))))))
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EZ
743
744(defun calcFunc-root (expr var guess)
bf77c646 745 (math-find-root expr var guess nil))
136211a9
EZ
746
747(defun calcFunc-wroot (expr var guess)
bf77c646 748 (math-find-root expr var guess t))
136211a9
EZ
749
750
751
752
753;;; The following algorithms come from Numerical Recipes, chapter 10.
754
755(defun math-min-eval (expr a)
756 (if (Math-vectorp a)
757 (let ((m -1))
758 (while (setq m (1+ m) a (cdr a))
759 (set (nth 2 (aref math-min-vars m)) (car a))))
760 (setq var-DUMMY a))
761 (setq a (math-evaluate-expr expr))
762 (if (Math-ratp a)
763 (math-float a)
764 (if (eq (car a) 'float)
765 a
bf77c646 766 (math-reject-arg a 'realp))))
136211a9 767
3132f345 768(defvar math-min-or-max "minimum")
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EZ
769
770;;; A bracket for a minimum is a < b < c where f(b) < f(a) and f(b) < f(c).
771
772;;; "mnbrak"
773(defun math-widen-min (expr a b)
774 (let ((done nil)
775 (iters 30)
776 incr c va vb vc u vu r q ulim bc ba qr)
777 (or b (setq b (math-mul a '(float 101 -2))))
778 (setq va (math-min-eval expr a)
779 vb (math-min-eval expr b))
780 (if (math-lessp-float va vb)
781 (setq u a a b b u
782 vu va va vb vb vu))
783 (setq c (math-add-float b (math-mul-float '(float 161803 -5)
784 (math-sub-float b a)))
785 vc (math-min-eval expr c))
786 (while (and (not done) (math-lessp-float vc vb))
787 (math-working "widen" (list 'intv 0 a c))
788 (if (= (setq iters (1- iters)) 0)
789 (math-reject-arg nil (format "*Unable to find a %s near the interval"
790 math-min-or-max)))
791 (setq bc (math-sub-float b c)
792 ba (math-sub-float b a)
793 r (math-mul-float ba (math-sub-float vb vc))
794 q (math-mul-float bc (math-sub-float vb va))
795 qr (math-sub-float q r))
796 (if (math-lessp-float (math-abs qr) '(float 1 -20))
797 (setq qr (if (math-negp qr) '(float -1 -20) '(float 1 -20))))
798 (setq u (math-sub-float
799 b
800 (math-div-float (math-sub-float (math-mul-float bc q)
801 (math-mul-float ba r))
802 (math-mul-float '(float 2 0) qr)))
803 ulim (math-add-float b (math-mul-float '(float -1 2) bc))
804 incr (math-negp bc))
805 (if (if incr (math-lessp-float b u) (math-lessp-float u b))
806 (if (if incr (math-lessp-float u c) (math-lessp-float c u))
807 (if (math-lessp-float (setq vu (math-min-eval expr u)) vc)
808 (setq a b va vb
809 b u vb vu
810 done t)
811 (if (math-lessp-float vb vu)
812 (setq c u vc vu
813 done t)
814 (setq u (math-add-float c (math-mul-float '(float -161803 -5)
815 bc))
816 vu (math-min-eval expr u))))
817 (if (if incr (math-lessp-float u ulim) (math-lessp-float ulim u))
818 (if (math-lessp-float (setq vu (math-min-eval expr u)) vc)
819 (setq b c vb vc
820 c u vc vu
821 u (math-add-float c (math-mul-float
822 '(float -161803 -5)
823 (math-sub-float b c)))
824 vu (math-min-eval expr u)))
825 (setq u ulim
826 vu (math-min-eval expr u))))
827 (setq u (math-add-float c (math-mul-float '(float -161803 -5)
828 bc))
829 vu (math-min-eval expr u)))
830 (setq a b va vb
831 b c vb vc
832 c u vc vu))
833 (if (math-lessp-float a c)
834 (list a va b vb c vc)
bf77c646 835 (list c vc b vb a va))))
136211a9
EZ
836
837(defun math-narrow-min (expr a c intv)
838 (let ((xvals (list a c))
839 (yvals (list (math-min-eval expr a)
840 (math-min-eval expr c)))
841 (levels 0)
842 (step (math-sub-float c a))
843 (found nil)
844 xp yp b)
845 (while (and (<= (setq levels (1+ levels)) 5)
846 (not found))
847 (setq xp xvals
848 yp yvals
849 step (math-mul-float step '(float 497 -3)))
850 (while (and (cdr xp) (not found))
851 (setq b (math-add-float (car xp) step))
852 (math-working "search" b)
853 (setcdr xp (cons b (cdr xp)))
854 (setcdr yp (cons (math-min-eval expr b) (cdr yp)))
855 (if (and (math-lessp-float (nth 1 yp) (car yp))
856 (math-lessp-float (nth 1 yp) (nth 2 yp)))
857 (setq found t)
858 (setq xp (cdr xp)
859 yp (cdr yp))
860 (if (and (cdr (cdr yp))
861 (math-lessp-float (nth 1 yp) (car yp))
862 (math-lessp-float (nth 1 yp) (nth 2 yp)))
863 (setq found t)
864 (setq xp (cdr xp)
865 yp (cdr yp))))))
866 (if found
867 (list (car xp) (car yp)
868 (nth 1 xp) (nth 1 yp)
869 (nth 2 xp) (nth 2 yp))
870 (or (if (math-lessp-float (car yvals) (nth 1 yvals))
871 (and (memq (nth 1 intv) '(2 3))
872 (let ((min (car yvals)))
873 (while (and (setq yvals (cdr yvals))
874 (math-lessp-float min (car yvals))))
875 (and (not yvals)
876 (list (nth 2 intv) min))))
877 (and (memq (nth 1 intv) '(1 3))
878 (setq yvals (nreverse yvals))
879 (let ((min (car yvals)))
880 (while (and (setq yvals (cdr yvals))
881 (math-lessp-float min (car yvals))))
882 (and (not yvals)
883 (list (nth 3 intv) min)))))
884 (math-reject-arg nil (format "*Unable to find a %s in the interval"
bf77c646 885 math-min-or-max))))))
136211a9
EZ
886
887;;; "brent"
888(defun math-brent-min (expr prec a va x vx b vb)
889 (let ((iters (+ 20 (* 5 prec)))
890 (w x)
891 (vw vx)
892 (v x)
893 (vv vx)
894 (tol (list 'float 1 (- -1 prec)))
895 (zeps (list 'float 1 (- -5 prec)))
896 (e '(float 0 0))
897 u vu xm tol1 tol2 etemp p q r xv xw)
898 (while (progn
899 (setq xm (math-mul-float '(float 5 -1)
900 (math-add-float a b))
901 tol1 (math-add-float
902 zeps
903 (math-mul-float tol (math-abs x)))
904 tol2 (math-mul-float tol1 '(float 2 0)))
905 (math-lessp-float (math-sub-float tol2
906 (math-mul-float
907 '(float 5 -1)
908 (math-sub-float b a)))
909 (math-abs (math-sub-float x xm))))
910 (if (= (setq iters (1- iters)) 0)
911 (math-reject-arg nil (format "*Unable to converge on a %s"
912 math-min-or-max)))
913 (math-working "brent" x)
914 (if (math-lessp-float (math-abs e) tol1)
915 (setq e (if (math-lessp-float x xm)
916 (math-sub-float b x)
917 (math-sub-float a x))
918 d (math-mul-float '(float 381966 -6) e))
919 (setq xw (math-sub-float x w)
920 r (math-mul-float xw (math-sub-float vx vv))
921 xv (math-sub-float x v)
922 q (math-mul-float xv (math-sub-float vx vw))
923 p (math-sub-float (math-mul-float xv q)
924 (math-mul-float xw r))
925 q (math-mul-float '(float 2 0) (math-sub-float q r)))
926 (if (math-posp q)
927 (setq p (math-neg-float p))
928 (setq q (math-neg-float q)))
929 (setq etemp e
930 e d)
931 (if (and (math-lessp-float (math-abs p)
932 (math-abs (math-mul-float
933 '(float 5 -1)
934 (math-mul-float q etemp))))
935 (math-lessp-float (math-mul-float
936 q (math-sub-float a x)) p)
937 (math-lessp-float p (math-mul-float
938 q (math-sub-float b x))))
939 (progn
940 (setq d (math-div-float p q)
941 u (math-add-float x d))
942 (if (or (math-lessp-float (math-sub-float u a) tol2)
943 (math-lessp-float (math-sub-float b u) tol2))
944 (setq d (if (math-lessp-float xm x)
945 (math-neg-float tol1)
946 tol1))))
947 (setq e (if (math-lessp-float x xm)
948 (math-sub-float b x)
949 (math-sub-float a x))
950 d (math-mul-float '(float 381966 -6) e))))
951 (setq u (math-add-float x
952 (if (math-lessp-float (math-abs d) tol1)
953 (if (math-negp d)
954 (math-neg-float tol1)
955 tol1)
956 d))
957 vu (math-min-eval expr u))
958 (if (math-lessp-float vx vu)
959 (progn
960 (if (math-lessp-float u x)
961 (setq a u)
962 (setq b u))
963 (if (or (equal w x)
964 (not (math-lessp-float vw vu)))
965 (setq v w vv vw
966 w u vw vu)
967 (if (or (equal v x)
968 (equal v w)
969 (not (math-lessp-float vv vu)))
970 (setq v u vv vu))))
971 (if (math-lessp-float u x)
972 (setq b x)
973 (setq a x))
974 (setq v w vv vw
975 w x vw vx
976 x u vx vu)))
bf77c646 977 (list 'vec x vx)))
136211a9
EZ
978
979;;; "powell"
980(defun math-powell-min (expr n guesses prec)
981 (let* ((f1dim (math-line-min-func expr n))
982 (xi (calcFunc-idn 1 n))
983 (p (cons 'vec (mapcar 'car guesses)))
984 (pt p)
985 (ftol (list 'float 1 (- prec)))
986 (fret (math-min-eval expr p))
987 fp ptt fptt xit i ibig del diff res)
988 (while (progn
989 (setq fp fret
990 ibig 0
991 del '(float 0 0)
992 i 0)
993 (while (<= (setq i (1+ i)) n)
994 (setq fptt fret
995 res (math-line-min f1dim p
996 (math-mat-col xi i)
997 n prec)
998 p (let ((calc-internal-prec prec))
999 (math-normalize (car res)))
1000 fret (nth 2 res)
1001 diff (math-abs (math-sub-float fptt fret)))
1002 (if (math-lessp-float del diff)
1003 (setq del diff
1004 ibig i)))
1005 (math-lessp-float
1006 (math-mul-float ftol
1007 (math-add-float (math-abs fp)
1008 (math-abs fret)))
1009 (math-mul-float '(float 2 0)
1010 (math-abs (math-sub-float fp
1011 fret)))))
1012 (setq ptt (math-sub (math-mul '(float 2 0) p) pt)
1013 xit (math-sub p pt)
1014 pt p
1015 fptt (math-min-eval expr ptt))
1016 (if (and (math-lessp-float fptt fp)
1017 (math-lessp-float
1018 (math-mul-float
1019 (math-mul-float '(float 2 0)
1020 (math-add-float
1021 (math-sub-float fp
1022 (math-mul-float '(float 2 0)
1023 fret))
1024 fptt))
1025 (math-sqr-float (math-sub-float
1026 (math-sub-float fp fret) del)))
1027 (math-mul-float del
1028 (math-sqr-float (math-sub-float fp fptt)))))
1029 (progn
1030 (setq res (math-line-min f1dim p xit n prec)
1031 p (car res)
1032 fret (nth 2 res)
1033 i 0)
1034 (while (<= (setq i (1+ i)) n)
1035 (setcar (nthcdr ibig (nth i xi))
1036 (nth i (nth 1 res)))))))
bf77c646 1037 (list 'vec p fret)))
136211a9
EZ
1038
1039(defun math-line-min-func (expr n)
1040 (let ((m -1))
1041 (while (< (setq m (1+ m)) n)
1042 (set (nth 2 (aref math-min-vars m))
1043 (list '+
1044 (list '*
1045 '(var DUMMY var-DUMMY)
1046 (list 'calcFunc-mrow '(var line-xi line-xi) (1+ m)))
1047 (list 'calcFunc-mrow '(var line-p line-p) (1+ m)))))
bf77c646 1048 (math-evaluate-expr expr)))
136211a9
EZ
1049
1050(defun math-line-min (f1dim line-p line-xi n prec)
1051 (let* ((var-DUMMY nil)
1052 (expr (math-evaluate-expr f1dim))
1053 (params (math-widen-min expr '(float 0 0) '(float 1 0)))
1054 (res (apply 'math-brent-min expr prec params))
1055 (xi (math-mul (nth 1 res) line-xi)))
bf77c646 1056 (list (math-add line-p xi) xi (nth 2 res))))
136211a9
EZ
1057
1058
1059(defvar math-min-vars [(var DUMMY var-DUMMY)])
1060
1061(defun math-find-minimum (expr var guess min-widen)
1062 (let* ((calc-symbolic-mode nil)
1063 (n 0)
1064 (var-DUMMY nil)
1065 (isvec (math-vectorp var))
1066 g guesses)
1067 (or (math-vectorp var)
1068 (setq var (list 'vec var)))
1069 (or (math-vectorp guess)
1070 (setq guess (list 'vec guess)))
1071 (or (= (length var) (length guess))
1072 (math-dimension-error))
1073 (while (setq var (cdr var) guess (cdr guess))
1074 (or (eq (car-safe (car var)) 'var)
1075 (math-reject-arg (car vg) "*Expected a variable"))
1076 (or (math-expr-contains expr (car var))
1077 (math-reject-arg (car var)
1078 "*Formula does not contain specified variable"))
1079 (while (>= (1+ n) (length math-min-vars))
1080 (let ((symb (intern (concat "math-min-v"
1081 (int-to-string
1082 (length math-min-vars))))))
1083 (setq math-min-vars (vconcat math-min-vars
1084 (vector (list 'var symb symb))))))
1085 (set (nth 2 (aref math-min-vars n)) nil)
1086 (set (nth 2 (aref math-min-vars (1+ n))) nil)
1087 (if (math-complexp (car guess))
1088 (setq expr (math-expr-subst expr
1089 (car var)
1090 (list '+ (aref math-min-vars n)
1091 (list '*
1092 (aref math-min-vars (1+ n))
1093 '(cplx 0 1))))
1094 guesses (let ((g (math-float (math-complex (car guess)))))
1095 (cons (list (nth 2 g) nil nil)
1096 (cons (list (nth 1 g) nil nil t)
1097 guesses)))
1098 n (+ n 2))
1099 (setq expr (math-expr-subst expr
1100 (car var)
1101 (aref math-min-vars n))
1102 guesses (cons (if (math-realp (car guess))
1103 (list (math-float (car guess)) nil nil)
1104 (if (and (eq (car-safe (car guess)) 'intv)
1105 (math-constp (car guess)))
1106 (list (math-mul
1107 (math-add (nth 2 (car guess))
1108 (nth 3 (car guess)))
1109 '(float 5 -1))
1110 (math-float (nth 2 (car guess)))
1111 (math-float (nth 3 (car guess)))
1112 (car guess))
1113 (math-reject-arg (car guess) 'realp)))
1114 guesses)
1115 n (1+ n))))
1116 (setq guesses (nreverse guesses)
1117 expr (math-evaluate-expr expr))
1118 (if (= n 1)
1119 (let* ((params (if (nth 1 (car guesses))
1120 (if min-widen
1121 (math-widen-min expr
1122 (nth 1 (car guesses))
1123 (nth 2 (car guesses)))
1124 (math-narrow-min expr
1125 (nth 1 (car guesses))
1126 (nth 2 (car guesses))
1127 (nth 3 (car guesses))))
1128 (math-widen-min expr
1129 (car (car guesses))
1130 nil)))
1131 (prec calc-internal-prec)
1132 (res (if (cdr (cdr params))
1133 (math-with-extra-prec (+ calc-internal-prec 2)
1134 (apply 'math-brent-min expr prec params))
1135 (cons 'vec params))))
1136 (if isvec
1137 (list 'vec (list 'vec (nth 1 res)) (nth 2 res))
1138 res))
1139 (let* ((prec calc-internal-prec)
1140 (res (math-with-extra-prec (+ calc-internal-prec 2)
1141 (math-powell-min expr n guesses prec)))
1142 (p (nth 1 res))
1143 (vec (list 'vec)))
1144 (while (setq p (cdr p))
1145 (if (nth 3 (car guesses))
1146 (progn
1147 (nconc vec (list (math-normalize
1148 (list 'cplx (car p) (nth 1 p)))))
1149 (setq p (cdr p)
1150 guesses (cdr guesses)))
1151 (nconc vec (list (car p))))
1152 (setq guesses (cdr guesses)))
1153 (if isvec
1154 (list 'vec vec (nth 2 res))
bf77c646 1155 (list 'vec (nth 1 vec) (nth 2 res)))))))
136211a9
EZ
1156
1157(defun calcFunc-minimize (expr var guess)
1158 (let ((calc-internal-prec (max (/ calc-internal-prec 2) 3))
1159 (math-min-or-max "minimum"))
1160 (math-find-minimum (math-normalize expr)
1161 (math-normalize var)
bf77c646 1162 (math-normalize guess) nil)))
136211a9
EZ
1163
1164(defun calcFunc-wminimize (expr var guess)
1165 (let ((calc-internal-prec (max (/ calc-internal-prec 2) 3))
1166 (math-min-or-max "minimum"))
1167 (math-find-minimum (math-normalize expr)
1168 (math-normalize var)
bf77c646 1169 (math-normalize guess) t)))
136211a9
EZ
1170
1171(defun calcFunc-maximize (expr var guess)
1172 (let* ((calc-internal-prec (max (/ calc-internal-prec 2) 3))
1173 (math-min-or-max "maximum")
1174 (res (math-find-minimum (math-normalize (math-neg expr))
1175 (math-normalize var)
1176 (math-normalize guess) nil)))
bf77c646 1177 (list 'vec (nth 1 res) (math-neg (nth 2 res)))))
136211a9
EZ
1178
1179(defun calcFunc-wmaximize (expr var guess)
1180 (let* ((calc-internal-prec (max (/ calc-internal-prec 2) 3))
1181 (math-min-or-max "maximum")
1182 (res (math-find-minimum (math-normalize (math-neg expr))
1183 (math-normalize var)
1184 (math-normalize guess) t)))
bf77c646 1185 (list 'vec (nth 1 res) (math-neg (nth 2 res)))))
136211a9
EZ
1186
1187
1188
1189
1190;;; The following algorithms come from Numerical Recipes, chapter 3.
1191
1192(defun calcFunc-polint (data x)
1193 (or (math-matrixp data) (math-reject-arg data 'matrixp))
1194 (or (= (length data) 3)
1195 (math-reject-arg data "*Wrong number of data rows"))
1196 (or (> (length (nth 1 data)) 2)
1197 (math-reject-arg data "*Too few data points"))
1198 (if (and (math-vectorp x) (or (math-constp x) math-expand-formulas))
1199 (cons 'vec (mapcar (function (lambda (x) (calcFunc-polint data x)))
1200 (cdr x)))
1201 (or (math-objectp x) math-expand-formulas (math-reject-arg x 'objectp))
1202 (math-with-extra-prec 2
1203 (cons 'vec (math-poly-interp (cdr (nth 1 data)) (cdr (nth 2 data)) x
bf77c646 1204 nil)))))
136211a9
EZ
1205(put 'calcFunc-polint 'math-expandable t)
1206
1207
1208(defun calcFunc-ratint (data x)
1209 (or (math-matrixp data) (math-reject-arg data 'matrixp))
1210 (or (= (length data) 3)
1211 (math-reject-arg data "*Wrong number of data rows"))
1212 (or (> (length (nth 1 data)) 2)
1213 (math-reject-arg data "*Too few data points"))
1214 (if (and (math-vectorp x) (or (math-constp x) math-expand-formulas))
1215 (cons 'vec (mapcar (function (lambda (x) (calcFunc-ratint data x)))
1216 (cdr x)))
1217 (or (math-objectp x) math-expand-formulas (math-reject-arg x 'objectp))
1218 (math-with-extra-prec 2
1219 (cons 'vec (math-poly-interp (cdr (nth 1 data)) (cdr (nth 2 data)) x
bf77c646 1220 (cdr (cdr (cdr (nth 1 data)))))))))
136211a9
EZ
1221(put 'calcFunc-ratint 'math-expandable t)
1222
1223
1224(defun math-poly-interp (xa ya x ratp)
1225 (let ((n (length xa))
1226 (dif nil)
1227 (ns nil)
1228 (xax nil)
1229 (c (copy-sequence ya))
1230 (d (copy-sequence ya))
1231 (i 0)
1232 (m 0)
1233 y dy (xp xa) xpm cp dp temp)
1234 (while (<= (setq i (1+ i)) n)
1235 (setq xax (cons (math-sub (car xp) x) xax)
1236 xp (cdr xp)
1237 temp (math-abs (car xax)))
1238 (if (or (null dif) (math-lessp temp dif))
1239 (setq dif temp
1240 ns i)))
1241 (setq xax (nreverse xax)
1242 ns (1- ns)
1243 y (nth ns ya))
1244 (if (math-zerop dif)
1245 (list y 0)
1246 (while (< (setq m (1+ m)) n)
1247 (setq i 0
1248 xp xax
1249 xpm (nthcdr m xax)
1250 cp c
1251 dp d)
1252 (while (<= (setq i (1+ i)) (- n m))
1253 (if ratp
1254 (let ((t2 (math-div (math-mul (car xp) (car dp)) (car xpm))))
1255 (setq temp (math-div (math-sub (nth 1 cp) (car dp))
1256 (math-sub t2 (nth 1 cp))))
1257 (setcar dp (math-mul (nth 1 cp) temp))
1258 (setcar cp (math-mul t2 temp)))
1259 (if (math-equal (car xp) (car xpm))
1260 (math-reject-arg (cons 'vec xa) "*Duplicate X values"))
1261 (setq temp (math-div (math-sub (nth 1 cp) (car dp))
1262 (math-sub (car xp) (car xpm))))
1263 (setcar dp (math-mul (car xpm) temp))
1264 (setcar cp (math-mul (car xp) temp)))
1265 (setq cp (cdr cp)
1266 dp (cdr dp)
1267 xp (cdr xp)
1268 xpm (cdr xpm)))
1269 (if (< (+ ns ns) (- n m))
1270 (setq dy (nth ns c))
1271 (setq ns (1- ns)
1272 dy (nth ns d)))
1273 (setq y (math-add y dy)))
bf77c646 1274 (list y dy))))
136211a9
EZ
1275
1276
1277
1278;;; The following algorithms come from Numerical Recipes, chapter 4.
1279
1280(defun calcFunc-ninteg (expr var lo hi)
1281 (setq lo (math-evaluate-expr lo)
1282 hi (math-evaluate-expr hi))
1283 (or (math-numberp lo) (math-infinitep lo) (math-reject-arg lo 'numberp))
1284 (or (math-numberp hi) (math-infinitep hi) (math-reject-arg hi 'numberp))
1285 (if (math-lessp hi lo)
1286 (math-neg (calcFunc-ninteg expr var hi lo))
1287 (setq expr (math-expr-subst expr var '(var DUMMY var-DUMMY)))
1288 (let ((var-DUMMY nil)
1289 (calc-symbolic-mode nil)
1290 (calc-prefer-frac nil)
1291 (sum 0))
1292 (setq expr (math-evaluate-expr expr))
1293 (if (equal lo '(neg (var inf var-inf)))
1294 (let ((thi (if (math-lessp hi '(float -2 0))
1295 hi '(float -2 0))))
1296 (setq sum (math-ninteg-romberg
1297 'math-ninteg-midpoint expr
1298 (math-float lo) (math-float thi) 'inf)
1299 lo thi)))
1300 (if (equal hi '(var inf var-inf))
1301 (let ((tlo (if (math-lessp '(float 2 0) lo)
1302 lo '(float 2 0))))
1303 (setq sum (math-add sum
1304 (math-ninteg-romberg
1305 'math-ninteg-midpoint expr
1306 (math-float tlo) (math-float hi) 'inf))
1307 hi tlo)))
1308 (or (math-equal lo hi)
1309 (setq sum (math-add sum
1310 (math-ninteg-romberg
1311 'math-ninteg-midpoint expr
1312 (math-float lo) (math-float hi) nil))))
bf77c646 1313 sum)))
136211a9
EZ
1314
1315
1316;;; Open Romberg method; "qromo" in section 4.4.
a1506d29 1317(defun math-ninteg-romberg (func expr lo hi mode)
136211a9
EZ
1318 (let ((curh '(float 1 0))
1319 (h nil)
1320 (s nil)
1321 (j 0)
1322 (ss nil)
1323 (prec calc-internal-prec)
1324 (integ-temp nil))
1325 (math-with-extra-prec 2
1326 ;; Limit on "j" loop must be 14 or less to keep "it" from overflowing.
1327 (or (while (and (null ss) (<= (setq j (1+ j)) 8))
1328 (setq s (nconc s (list (funcall func expr lo hi mode)))
1329 h (nconc h (list curh)))
1330 (if (>= j 3)
1331 (let ((res (math-poly-interp h s '(float 0 0) nil)))
1332 (if (math-lessp (math-abs (nth 1 res))
1333 (calcFunc-scf (math-abs (car res))
1334 (- prec)))
1335 (setq math-ninteg-convergence j
1336 ss (car res)))))
1337 (if (>= j 5)
1338 (setq s (cdr s)
1339 h (cdr h)))
1340 (setq curh (math-div-float curh '(float 9 0))))
1341 ss
bf77c646 1342 (math-reject-arg nil (format "*Integral failed to converge"))))))
136211a9
EZ
1343
1344
1345(defun math-ninteg-evaluate (expr x mode)
1346 (if (eq mode 'inf)
1347 (setq x (math-div '(float 1 0) x)))
1348 (let* ((var-DUMMY x)
1349 (res (math-evaluate-expr expr)))
1350 (or (Math-numberp res)
1351 (math-reject-arg res "*Integrand does not evaluate to a number"))
1352 (if (eq mode 'inf)
1353 (setq res (math-mul res (math-sqr x))))
bf77c646 1354 res))
136211a9
EZ
1355
1356
1357(defun math-ninteg-midpoint (expr lo hi mode) ; uses "integ-temp"
1358 (if (eq mode 'inf)
1359 (let ((math-infinite-mode t) temp)
1360 (setq temp (math-div 1 lo)
1361 lo (math-div 1 hi)
1362 hi temp)))
1363 (if integ-temp
1364 (let* ((it3 (* 3 (car integ-temp)))
1365 (math-working-step-2 (* 2 (car integ-temp)))
1366 (math-working-step 0)
1367 (range (math-sub hi lo))
1368 (del (math-div range (math-float it3)))
1369 (del2 (math-add del del))
1370 (del3 (math-add del del2))
1371 (x (math-add lo (math-mul '(float 5 -1) del)))
1372 (sum '(float 0 0))
1373 (j 0) temp)
1374 (while (<= (setq j (1+ j)) (car integ-temp))
1375 (setq math-working-step (1+ math-working-step)
1376 temp (math-ninteg-evaluate expr x mode)
1377 math-working-step (1+ math-working-step)
1378 sum (math-add sum (math-add temp (math-ninteg-evaluate
1379 expr (math-add x del2)
1380 mode)))
1381 x (math-add x del3)))
1382 (setq integ-temp (list it3
1383 (math-add (math-div (nth 1 integ-temp)
1384 '(float 3 0))
1385 (math-mul sum del)))))
1386 (setq integ-temp (list 1 (math-mul
1387 (math-sub hi lo)
1388 (math-ninteg-evaluate
1389 expr
1390 (math-mul (math-add lo hi) '(float 5 -1))
1391 mode)))))
bf77c646 1392 (nth 1 integ-temp))
136211a9
EZ
1393
1394
1395
1396
1397
1398;;; The following algorithms come from Numerical Recipes, chapter 14.
1399
3132f345
CW
1400(defvar math-dummy-vars [(var DUMMY var-DUMMY)])
1401(defvar math-dummy-counter 0)
136211a9
EZ
1402(defun math-dummy-variable ()
1403 (if (= math-dummy-counter (length math-dummy-vars))
1404 (let ((symb (intern (format "math-dummy-%d" math-dummy-counter))))
1405 (setq math-dummy-vars (vconcat math-dummy-vars
1406 (vector (list 'var symb symb))))))
1407 (set (nth 2 (aref math-dummy-vars math-dummy-counter)) nil)
1408 (prog1
1409 (aref math-dummy-vars math-dummy-counter)
bf77c646 1410 (setq math-dummy-counter (1+ math-dummy-counter))))
136211a9 1411
3132f345
CW
1412(defvar math-in-fit 0)
1413(defvar calc-fit-to-trail nil)
136211a9
EZ
1414
1415(defun calcFunc-fit (expr vars &optional coefs data)
1416 (let ((math-in-fit 10))
1417 (math-with-extra-prec 2
bf77c646 1418 (math-general-fit expr vars coefs data nil))))
136211a9
EZ
1419
1420(defun calcFunc-efit (expr vars &optional coefs data)
1421 (let ((math-in-fit 10))
1422 (math-with-extra-prec 2
bf77c646 1423 (math-general-fit expr vars coefs data 'sdev))))
136211a9
EZ
1424
1425(defun calcFunc-xfit (expr vars &optional coefs data)
1426 (let ((math-in-fit 10))
1427 (math-with-extra-prec 2
bf77c646 1428 (math-general-fit expr vars coefs data 'full))))
136211a9
EZ
1429
1430(defun math-general-fit (expr vars coefs data mode)
1431 (let ((calc-simplify-mode nil)
1432 (math-dummy-counter math-dummy-counter)
1433 (math-in-fit 1)
1434 (extended (eq mode 'full))
1435 (first-coef math-dummy-counter)
1436 first-var
1437 (plain-expr expr)
1438 orig-expr
1439 have-sdevs need-chisq chisq
1440 (x-funcs nil)
1441 (y-filter nil)
1442 y-dummy
1443 (coef-filters nil)
1444 new-coefs
1445 (xy-values nil)
1446 (weights nil)
1447 (var-YVAL nil) (var-YVALX nil)
1448 covar beta
1449 n nn m mm v dummy p)
1450
1451 ;; Validate and parse arguments.
1452 (or data
1453 (if coefs
1454 (setq data coefs
1455 coefs nil)
1456 (if (math-vectorp expr)
1457 (if (memq (length expr) '(3 4))
1458 (setq data vars
1459 vars (nth 2 expr)
1460 coefs (nth 3 expr)
1461 expr (nth 1 expr))
1462 (math-dimension-error))
1463 (setq data vars
1464 vars nil
1465 coefs nil))))
1466 (or (math-matrixp data) (math-reject-arg data 'matrixp))
1467 (setq v (1- (length data))
1468 n (1- (length (nth 1 data))))
1469 (or (math-vectorp vars) (null vars)
1470 (setq vars (list 'vec vars)))
1471 (or (math-vectorp coefs) (null coefs)
1472 (setq coefs (list 'vec coefs)))
1473 (or coefs
1474 (setq coefs (cons 'vec (math-all-vars-but expr vars))))
1475 (or vars
1476 (if (<= (1- (length coefs)) v)
1477 (math-reject-arg coefs "*Not enough variables in model")
1478 (setq coefs (copy-sequence coefs))
1479 (let ((p (nthcdr (- (length coefs) v
1480 (if (eq (car-safe expr) 'calcFunc-eq) 1 0))
1481 coefs)))
1482 (setq vars (cons 'vec (cdr p)))
1483 (setcdr p nil))))
1484 (or (= (1- (length vars)) v)
1485 (= (length vars) v)
1486 (math-reject-arg vars "*Number of variables does not match data"))
1487 (setq m (1- (length coefs)))
1488 (if (< m 1)
1489 (math-reject-arg coefs "*Need at least one parameter"))
1490
1491 ;; Rewrite expr in terms of fitparam and fitvar, make into an equation.
1492 (setq p coefs)
1493 (while (setq p (cdr p))
1494 (or (eq (car-safe (car p)) 'var)
1495 (math-reject-arg (car p) "*Expected a variable"))
1496 (setq dummy (math-dummy-variable)
1497 expr (math-expr-subst expr (car p)
1498 (list 'calcFunc-fitparam
1499 (- math-dummy-counter first-coef)))))
1500 (setq first-var math-dummy-counter
1501 p vars)
1502 (while (setq p (cdr p))
1503 (or (eq (car-safe (car p)) 'var)
1504 (math-reject-arg (car p) "*Expected a variable"))
1505 (setq dummy (math-dummy-variable)
1506 expr (math-expr-subst expr (car p)
1507 (list 'calcFunc-fitvar
1508 (- math-dummy-counter first-var)))))
1509 (if (< math-dummy-counter (+ first-var v))
1510 (setq dummy (math-dummy-variable))) ; dependent variable may be unnamed
1511 (setq y-dummy dummy
1512 orig-expr expr)
1513 (or (eq (car-safe expr) 'calcFunc-eq)
1514 (setq expr (list 'calcFunc-eq (list 'calcFunc-fitvar v) expr)))
1515
1516 (let ((calc-symbolic-mode nil))
1517
1518 ;; Apply rewrites to put expr into a linear-like form.
1519 (setq expr (math-evaluate-expr expr)
1520 expr (math-rewrite (list 'calcFunc-fitmodel expr)
1521 '(var FitRules var-FitRules))
1522 math-in-fit 2
1523 expr (math-evaluate-expr expr))
1524 (or (and (eq (car-safe expr) 'calcFunc-fitsystem)
1525 (= (length expr) 4)
1526 (math-vectorp (nth 2 expr))
1527 (math-vectorp (nth 3 expr))
1528 (> (length (nth 2 expr)) 1)
1529 (= (length (nth 3 expr)) (1+ m)))
1530 (math-reject-arg plain-expr "*Model expression is too complex"))
1531 (setq y-filter (nth 1 expr)
1532 x-funcs (vconcat (cdr (nth 2 expr)))
1533 coef-filters (nth 3 expr)
1534 mm (length x-funcs))
1535 (if (equal y-filter y-dummy)
1536 (setq y-filter nil))
1537
1538 ;; Build the (square) system of linear equations to be solved.
1539 (setq beta (cons 'vec (make-list mm 0))
1540 covar (cons 'vec (mapcar 'copy-sequence (make-list mm beta))))
1541 (let* ((ptrs (vconcat (cdr data)))
1542 (isigsq 1)
1543 (xvals (make-vector mm 0))
1544 (i 0)
1545 j k xval yval sigmasqr wt covj covjk covk betaj lud)
1546 (while (<= (setq i (1+ i)) n)
1547
1548 ;; Assign various independent variables for this data point.
1549 (setq j 0
1550 sigmasqr nil)
1551 (while (< j v)
1552 (aset ptrs j (cdr (aref ptrs j)))
1553 (setq xval (car (aref ptrs j)))
1554 (if (= j (1- v))
1555 (if sigmasqr
1556 (progn
1557 (if (eq (car-safe xval) 'sdev)
1558 (setq sigmasqr (math-add (math-sqr (nth 2 xval))
1559 sigmasqr)
1560 xval (nth 1 xval)))
1561 (if y-filter
1562 (setq xval (math-make-sdev xval
1563 (math-sqrt sigmasqr))))))
1564 (if (eq (car-safe xval) 'sdev)
1565 (setq sigmasqr (math-add (math-sqr (nth 2 xval))
1566 (or sigmasqr 0))
1567 xval (nth 1 xval))))
1568 (set (nth 2 (aref math-dummy-vars (+ first-var j))) xval)
1569 (setq j (1+ j)))
1570
1571 ;; Compute Y value for this data point.
1572 (if y-filter
1573 (setq yval (math-evaluate-expr y-filter))
1574 (setq yval (symbol-value (nth 2 y-dummy))))
1575 (if (eq (car-safe yval) 'sdev)
1576 (setq sigmasqr (math-sqr (nth 2 yval))
1577 yval (nth 1 yval)))
1578 (if (= i 1)
1579 (setq have-sdevs sigmasqr
1580 need-chisq (or extended
1581 (and (eq mode 'sdev) (not have-sdevs)))))
1582 (if have-sdevs
1583 (if sigmasqr
1584 (progn
1585 (setq isigsq (math-div 1 sigmasqr))
1586 (if need-chisq
1587 (setq weights (cons isigsq weights))))
1588 (math-reject-arg yval "*Mixed error forms and plain numbers"))
1589 (if sigmasqr
1590 (math-reject-arg yval "*Mixed error forms and plain numbers")))
1591
1592 ;; Compute X values for this data point and update covar and beta.
1593 (if (eq (car-safe xval) 'sdev)
1594 (set (nth 2 y-dummy) (nth 1 xval)))
1595 (setq j 0
1596 covj covar
1597 betaj beta)
1598 (while (< j mm)
1599 (setq wt (math-evaluate-expr (aref x-funcs j)))
1600 (aset xvals j wt)
1601 (setq wt (math-mul wt isigsq)
1602 betaj (cdr betaj)
1603 covjk (car (setq covj (cdr covj)))
1604 k 0)
1605 (while (<= k j)
1606 (setq covjk (cdr covjk))
1607 (setcar covjk (math-add (car covjk)
1608 (math-mul wt (aref xvals k))))
1609 (setq k (1+ k)))
1610 (setcar betaj (math-add (car betaj) (math-mul wt yval)))
1611 (setq j (1+ j)))
1612 (if need-chisq
1613 (setq xy-values (cons (append xvals (list yval)) xy-values))))
1614
1615 ;; Fill in symmetric half of covar matrix.
1616 (setq j 0
1617 covj covar)
1618 (while (< j (1- mm))
1619 (setq k j
1620 j (1+ j)
1621 covjk (nthcdr j (car (setq covj (cdr covj))))
1622 covk (nthcdr j covar))
1623 (while (< (setq k (1+ k)) mm)
1624 (setq covjk (cdr covjk)
1625 covk (cdr covk))
1626 (setcar covjk (nth j (car covk))))))
1627
1628 ;; Solve the linear system.
1629 (if mode
1630 (progn
1631 (setq covar (math-matrix-inv-raw covar))
1632 (if covar
1633 (setq beta (math-mul covar beta))
1634 (if (math-zerop (math-abs beta))
1635 (setq covar (calcFunc-diag 0 (1- (length beta))))
1636 (math-reject-arg orig-expr "*Singular matrix")))
1637 (or (math-vectorp covar)
1638 (setq covar (list 'vec (list 'vec covar)))))
1639 (setq beta (math-div beta covar)))
1640
1641 ;; Compute chi-square statistic if necessary.
1642 (if need-chisq
1643 (let (bp xp sum)
1644 (setq chisq 0)
1645 (while xy-values
1646 (setq bp beta
1647 xp (car xy-values)
1648 sum 0)
1649 (while (setq bp (cdr bp))
1650 (setq sum (math-add sum (math-mul (car bp) (car xp)))
1651 xp (cdr xp)))
1652 (setq sum (math-sqr (math-sub (car xp) sum)))
1653 (if weights (setq sum (math-mul sum (car weights))))
1654 (setq chisq (math-add chisq sum)
1655 weights (cdr weights)
1656 xy-values (cdr xy-values)))))
1657
1658 ;; Convert coefficients back into original terms.
1659 (setq new-coefs (copy-sequence beta))
1660 (let* ((bp new-coefs)
1661 (cp covar)
1662 (sigdat 1)
1663 (math-in-fit 3)
1664 (j 0))
1665 (and mode (not have-sdevs)
1666 (setq sigdat (if (<= n mm)
1667 0
1668 (math-div chisq (- n mm)))))
1669 (if mode
1670 (while (setq bp (cdr bp))
1671 (setcar bp (math-make-sdev
1672 (car bp)
1673 (math-sqrt (math-mul (nth (setq j (1+ j))
1674 (car (setq cp (cdr cp))))
1675 sigdat))))))
1676 (setq new-coefs (math-evaluate-expr coef-filters))
1677 (if calc-fit-to-trail
1678 (let ((bp new-coefs)
1679 (cp coefs)
1680 (vec nil))
1681 (while (setq bp (cdr bp) cp (cdr cp))
1682 (setq vec (cons (list 'calcFunc-eq (car cp) (car bp)) vec)))
1683 (setq calc-fit-to-trail (cons 'vec (nreverse vec)))))))
1684
1685 ;; Substitute best-fit coefficients back into original formula.
1686 (setq expr (math-multi-subst
1687 orig-expr
1688 (let ((n v)
1689 (vec nil))
1690 (while (>= n 1)
1691 (setq vec (cons (list 'calcFunc-fitvar n) vec)
1692 n (1- n)))
1693 (setq n m)
1694 (while (>= n 1)
1695 (setq vec (cons (list 'calcFunc-fitparam n) vec)
1696 n (1- n)))
1697 vec)
1698 (append (cdr new-coefs) (cdr vars))))
1699
1700 ;; Package the result.
1701 (math-normalize
1702 (if extended
1703 (list 'vec expr beta covar
1704 (let ((p coef-filters)
1705 (n 0))
1706 (while (and (setq n (1+ n) p (cdr p))
1707 (eq (car-safe (car p)) 'calcFunc-fitdummy)
1708 (eq (nth 1 (car p)) n)))
1709 (if p
1710 coef-filters
1711 (list 'vec)))
1712 chisq
1713 (if (and have-sdevs (> n mm))
1714 (list 'calcFunc-utpc chisq (- n mm))
1715 '(var nan var-nan)))
bf77c646 1716 expr))))
136211a9 1717
136211a9
EZ
1718
1719(defun calcFunc-fitvar (x)
1720 (if (>= math-in-fit 2)
1721 (progn
1722 (setq x (aref math-dummy-vars (+ first-var x -1)))
1723 (or (calc-var-value (nth 2 x)) x))
bf77c646 1724 (math-reject-arg x)))
136211a9
EZ
1725
1726(defun calcFunc-fitparam (x)
1727 (if (>= math-in-fit 2)
1728 (progn
1729 (setq x (aref math-dummy-vars (+ first-coef x -1)))
1730 (or (calc-var-value (nth 2 x)) x))
bf77c646 1731 (math-reject-arg x)))
136211a9
EZ
1732
1733(defun calcFunc-fitdummy (x)
1734 (if (= math-in-fit 3)
1735 (nth x new-coefs)
bf77c646 1736 (math-reject-arg x)))
136211a9
EZ
1737
1738(defun calcFunc-hasfitvars (expr)
1739 (if (Math-primp expr)
1740 0
1741 (if (eq (car expr) 'calcFunc-fitvar)
1742 (nth 1 expr)
bf77c646 1743 (apply 'max (mapcar 'calcFunc-hasfitvars (cdr expr))))))
136211a9
EZ
1744
1745(defun calcFunc-hasfitparams (expr)
1746 (if (Math-primp expr)
1747 0
1748 (if (eq (car expr) 'calcFunc-fitparam)
1749 (nth 1 expr)
bf77c646 1750 (apply 'max (mapcar 'calcFunc-hasfitparams (cdr expr))))))
136211a9
EZ
1751
1752
1753(defun math-all-vars-but (expr but)
1754 (let* ((vars (math-all-vars-in expr))
1755 (p but))
1756 (while p
1757 (setq vars (delq (assoc (car-safe p) vars) vars)
1758 p (cdr p)))
1759 (sort (mapcar 'car vars)
bf77c646 1760 (function (lambda (x y) (string< (nth 1 x) (nth 1 y)))))))
136211a9
EZ
1761
1762(defun math-all-vars-in (expr)
1763 (let ((vars nil)
1764 found)
1765 (math-all-vars-rec expr)
bf77c646 1766 vars))
136211a9
EZ
1767
1768(defun math-all-vars-rec (expr)
1769 (if (Math-primp expr)
1770 (if (eq (car-safe expr) 'var)
1771 (or (math-const-var expr)
1772 (if (setq found (assoc expr vars))
1773 (setcdr found (1+ (cdr found)))
1774 (setq vars (cons (cons expr 1) vars)))))
1775 (while (setq expr (cdr expr))
bf77c646 1776 (math-all-vars-rec (car expr)))))
136211a9 1777
ab5796a9 1778;;; arch-tag: ff9f2920-8111-48b5-b3fa-b0682c3e44a6
bf77c646 1779;;; calcalg3.el ends here