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; file lll.lisp
; Maxima Interface
(defun maxima::$latticereduce (L) ; L is maxima list of maxima lists
(if (or
(not (listp L))
(< (length L) 2)
(not (equal (apply 'max (mapcar 'length (cdr L)))
(apply 'min (mapcar 'length (cdr L))) )) )
(maxima::merror "Latticereduce needs a list lists as input"))
(let* ((vs (mapcar 'cdr (cdr L)))
(n (length vs))
(v (make-array (list n))))
(loop for i from 0 to (- n 1) do
(setf (aref v i) (make-array (list n) :initial-contents (nth i vs))))
(setf v (lll v))
(cons '(maxima::mlist)
(mapcar #'(lambda (u) (cons '(maxima::mlist) (coerce u 'list)))
(coerce v 'list)))
))
(defun maxima::$integerrelations (L)
(let ((res (integerrelations (cdr L))))
(cons '(maxima::mlist) (car res))
))
(defun maxima::$floatrelations (L)
(let ((res (floatrelations (cdr L))))
(cons '(maxima::mlist) (car res))
))
(defun maxima::$recognize (x)
(convert2AlgNum x))
; linear algebra helpers
(defun norm2 (a)
(declare (type (vector number *) a))
(loop for i from 0 to (- (length a) 1) sum
(* (aref a i) (aref a i) )))
(defun vadd (a b)
(declare (type (vector number *) a))
(declare (type (vector number *) b))
(if (not (= (length a) (length b)))
(error "vadd: length must coincide")
(let ((res (make-array (list (length a)) ))
(n (length a)))
(loop for i from 0 to (- n 1) do
(setf (aref res i) (+ (aref a i) (aref b i))))
res)))
(defun vsub (a b)
(declare (type (vector number *) a))
(declare (type (vector number *) b))
(if (not (= (length a) (length b)))
(error "vadd: length must coincide")
(let ((res (make-array (list (length a)) ))
(n (length a)))
(loop for i from 0 to (- n 1) do
(setf (aref res i) (- (aref a i) (aref b i))))
res)))
(defun smul (s a)
(declare (type (vector number *) a))
(declare (type (vector number *) b))
(let ((res (make-array (list (length a)) ))
(n (length a)))
(loop for i from 0 to (- n 1) do
(setf (aref res i) (* s (aref a i))))
res))
(defun dot (a b)
(declare (type (vector number *) a))
(declare (type (vector number *) b))
(if (not (= (length a) (length b)))
(error "vadd: length must coincide")
(loop for i from 0 to (- (length a) 1) sum
(* (aref a i) (aref b i)))))
(defvar *gsbasis* nil)
(defun gso (f mu) ; returns Gram-Schmidt OGS, updates mu
(declare (type vector a))
(declare (type (array number (* *) mu)))
(let* ((n (length f))
(g (make-array (list n) )))
(loop for j from 0 to (- n 1) do (setf (aref g j) (aref f j)))
(loop for j from 0 to (- n 1) do
(loop for k from 0 to (- j 1) do
(if (> (norm2 (aref g k)) 0)
(progn
(setf (aref mu j k)
(/ (dot (aref f j) (aref g k))
(dot (aref g k) (aref g k))))
(setf (aref g j) (vsub (aref g j) (smul (aref mu j k) (aref g k))))
))
))
g
))
(defun lll (f) ; f is vetor of n vectors
(declare (type (vector vector *) f))
(let* ((n (length f))
(g (make-array (list n) ))
(gg nil)
(i 1)
(temp nil)
(mu (make-array (list n n) :initial-element 0)))
(loop for j from 0 to (- n 1) do
(setf (aref g j) (aref f j))
(setf (aref mu j j) 1))
(setf gg (gso g mu))
(do () ((>= i n) )
(loop for j from (- i 1) downto 0 do
(setf (aref g i)
(vsub (aref g i) (smul (nint (aref mu i j)) (aref g j))))
(setf gg (gso g mu))
)
(if (and (> i 0) (> (norm2 (aref gg (- i 1))) (* 2 (norm2 (aref gg i)))))
(progn
(setf temp (aref g (- i 1)))
(setf (aref g (- i 1)) (aref g i))
(setf (aref g i) temp)
(setf gg (gso g mu))
(setf i (- i 1))
)
(setf i (+ i 1)))
)
g
)
)
(defun nint (q)
(car (list (floor (+ q (/ 1 2))))))
(defun test1 ()
(lll #( #(12 2) #(13 4))))
(defun test2 ()
(lll #( #(12 2) #(1 2))))
(defun test3 ()
(lll #( #(1 2) #(12 2) )))
(defun test4 ()
(lll #( #(1 2) #(9 -4))))
(defun integerRelations (L) ; L ist list of integers
; returns (rel def) such that dotproduct def of rel and L is small
(let* ((n (length L))
(z nil) (g nil) (res nil) (optdef 0) (optres nil) (def 0)
(f (make-array (list (+ n 1)))))
(setf (aref f 0) (make-array (list (+ n 1)) :initial-element 0))
(loop for i from 1 to n do
(setf z (make-array (list (+ n 1)) :initial-element 0))
(setf (aref z 0) (nth (- i 1) L))
(setf (aref z i) 1)
(setf (aref f i) z))
(setf g (lll f))
(setf optdef most-POSITIVE-fixnum)
(loop for k from 1 to n do
(setf def 0)
(setf res nil)
(loop for i from n downto 1 do
(setf res (cons (aref (aref g k) i) res))
(setf def (+ def (* (nth (- i 1) L) (aref (aref g k) i))))
)
(if (< (abs def) (abs optdef))
(progn
(setf optdef def)
(setf optres res)
))
)
(list optres optdef)
))
(defun test5 ()
(print "Should give ((3 -7 4) 0)")
(integerRelations '(5707963267 4142135623 2967764890)))
(defun nkomma (a)
(- a (car (list (floor a)))))
(defun FloatRelations (x &optional (digits 10)) ; x is a list of floats or doubles
(let ((n (length x)) (digs nil) (i 0) (nkomma 0)
(nkommaStellen0) (xx 0) (expo nil) (rel nil) (def 0))
(setf nkommaStellen
(lambda (x) ; x ist float
(let ((s 0) (i 0))
(do () ((< (abs (nkomma (* x (expt 10d0 s)))) (expt 1d-1 digits)))
(setf s (+ s 1)))
s)))
(setf digs (mapcar nkommaStellen x))
(setf expo (apply 'max digs))
(setf xx (mapcar #'(lambda (u) (car (list (floor (* u (expt 10d0 expo)))))) x))
(setf rel (IntegerRelations xx))
(list (car rel) (/ (cadr rel) (expt 10.0d0 expo)))
))
(defun test6 ()
(FloatRelations (list .5707963267d0 .4142135623d0 .2967764890d0)))
(defun mkdif (a b) (list '(MAXIMA::MPLUS) a (list '(MAXIMA::MMINUS) b)) )
(defun mksum (a b) (list '(MAXIMA::MPLUS) a b) )
(defun mkprod (a b) (list '(MAXIMA::MTIMES) a b) )
(defun mkexpt (a b) (list '(MAXIMA::MEXPT) a b))
(defun mkeq (a b) (list '(MAXIMA::MEQUAL) a b))
(defun max2str (expr)
(maxima::mfuncall 'maxima::$string expr)
)
(defun convert2AlgNum (x &optional (digits 10)) ; x is float or double
(let ((n 0) (nn 6) ;; nn: maximal search degree
(xs nil) (res nil) (def 0) (sol nil)
(opt nil) (mini 0)
(var ($gensym "v")))
(loop for n from 2 to nn do
(if (not (null opt)) (return opt))
(setf xs (loop for i from 0 to n collect (expt x i)))
(setf res (FloatRelations xs digits))
(setf def (cadr res))
(if (< (abs def) (expt 10d0 (- digits)))
(progn
(setf pol 0)
(loop for i from 0 to n do
(setf pol (mksum pol (mkprod (nth i (car res)) (mkexpt var i)))))
(setf sol (maxima::meval (maxima::$solve (mkeq pol 0) var)))
(if (not (null (cdr sol))) ; a solution has been found
(progn (setq *sol* sol)
(setf sol (mapcar 'third (cdr sol)))
(setf sol
(mapcar #'(lambda (u)
(let ((r (maxima::$realpart u))
(i (maxima::$float (maxima::$imagpart u))))
(if (or (equal i 0) (equal i 0.0) (equal i 0.0d0))
(list u (abs (- x (maxima::$float u))))
(list u most-POSITIVE-DOUBLE-FLOAT)
)))
sol))
(setf mini most-POSITIVE-DOUBLE-FLOAT)
(loop for p in sol do (if (< (second p) mini) (progn (setf opt (car p)) (setq mini (second p)))))
))))
); loop
opt
) ; let
) ;defun
(defun test7 () ; fails
(convert2AlgNum 1.414213562373d0))
(defun test8 () ; works
(convert2AlgNum (+ 2 (* 3 1.414213562373d0))))
(defun test9 () :fails
(convert2AlgNum (+ 1d0 (sqrt 2d0) (sqrt 3d0)) ))
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