Changeset 1059

Timestamp:

2015-06-10T09:01:30-07:00 (9 years ago)

Author:

Marek Rychlik

Message:

* empty log message *

File:

• branches/f4grobner/parse.lisp (modified) (1 diff)

branches/f4grobner/parse.lisp

@@ -106 +106 @@
 ;; assuming variables are VARS
 
-(defun alist-form (plist vars)
-  "Translates an expression PLIST, which should be a list of polynomials
-in variables VARS, to an alist representation of a polynomial.
-It returns the alist. See also PARSE-TO-ALIST."
-  (cond
-   ((endp plist) nil)
-   ((eql (first plist) '[)
-    (cons '[ (mapcar #'(lambda (x) (alist-form x vars)) (rest plist))))
-   (t
-    (assert (eql (car plist) '+))
-    (alist-form-1 (rest plist) vars))))
-
-(defun alist-form-1 (p vars
-                         &aux (ht (make-hash-table
-                                   :test #'equal :size 16))
-                         stack)
-  (dolist (term p)
-    (assert (eql (car term) '*))
-    (incf  (gethash (powers (cddr term) vars) ht 0) (second term)))
-  (maphash #'(lambda (key value) (unless (zerop value)
-                                   (push (cons key value) stack))) ht)
-  stack)
-    
-(defun powers (monom vars
-                     &aux (tab (pairlis vars (make-list (length vars)
-                                                        :initial-element 0))))
-  (dolist (e monom (mapcar #'(lambda (v) (cdr (assoc v tab))) vars))
-    (assert (equal (first e) '^))
-    (assert (integerp (third e)))
-    (assert (= (length e) 3))
-    (let ((x (assoc (second e) tab)))
-      (if (null x) (error "Variable ~a not in the list of variables." 
-                         (second e))
-        (incf (cdr x) (third e))))))
-  
 
 ;; New implementation based on the INFIX package of Mark Kantorowitz