source: branches/f4grobner/grobner-wrap.lisp

;;; -*-  Mode: Lisp -*- 
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;;;  Copyright (C) 1999, 2002, 2009, 2015 Marek Rychlik <rychlik@u.arizona.edu>          
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;;;  This program is free software; you can redistribute it and/or modify        
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;; Selection of algorithm and pair heuristic
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(defpackage "GROBNER-WRAP"
  (:use :cl :buchberger :gebauer-moeller :gb-postprocessing :division :ring-and-order)
  (:export "$POLY_GROBNER_ALGORITHM" "GROBNER" "REDUCED-GROBNER"))

(in-package :grobner-wrap)

(defvar $poly_grobner_algorithm '$buchberger
  "The name of the algorithm used to find grobner bases.")

(defun choose-grobner-algorithm (algorithm)
  "Translates symbol ALGORITHM, which names the algorithm, and should
be either a keyword, an uninterne symbol or symbol in package
GROBNER-WRAP, or a Maxima-style symbols starting with the dollar. It
returns a function which calculates Grobner basis."
  (ecase algorithm
    ((buchberger :buchberger $buchberger #:buchberger) 
     #'buchberger)
    ((parallel-buchberger :parallel-buchberger $parallel_buchberger #:parallel_buchberger #:parallel-buchberger)
     #'parallel-buchberger)
    ((gebauer-moeller :gebauer-moeller :gebauer_moeller $gebauer_moeller #:gebauer_moeller #:gebauer-moeller)
    #'gebauer-moeller)))

(defun grobner (ring-and-order f 
                &optional 
                  (start 0) 
                  (top-reduction-only $poly_top_reduction_only))
  "Compute the Groebner basis of an ideal generated by F. Optionally,
assume that first START elements are already a grobner basis. 
If TOP-REDUCTION-ONLY is T then perform top reduction only."
  (declare (type ring-and-order ring-and-order))
  ;;(setf F (sort F #'< :key #'sugar))
  (funcall 
   (choose-grobner-algorithm $poly_grobner_algorithm)
   ring-and-order f start top-reduction-only))

(defun reduced-grobner (ring-and-order f 
                        &optional 
                          (start 0) 
                          (top-reduction-only $poly_top_reduction_only))
  (declare (type ring-and-order ring-and-order))
  (reduction ring-and-order 
             (grobner ring-and-order 
                       f 
                       start 
                       top-reduction-only)))