[1201] | 1 | ;;; -*- Mode: Lisp -*-
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[78] | 2 | ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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| 3 | ;;;
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| 4 | ;;; Copyright (C) 1999, 2002, 2009, 2015 Marek Rychlik <rychlik@u.arizona.edu>
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| 5 | ;;;
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| 6 | ;;; This program is free software; you can redistribute it and/or modify
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| 7 | ;;; it under the terms of the GNU General Public License as published by
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| 8 | ;;; the Free Software Foundation; either version 2 of the License, or
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| 9 | ;;; (at your option) any later version.
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| 10 | ;;;
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| 11 | ;;; This program is distributed in the hope that it will be useful,
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| 12 | ;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 13 | ;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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| 14 | ;;; GNU General Public License for more details.
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| 15 | ;;;
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| 16 | ;;; You should have received a copy of the GNU General Public License
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| 17 | ;;; along with this program; if not, write to the Free Software
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| 18 | ;;; Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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| 19 | ;;;
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| 20 | ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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| 21 |
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[397] | 22 | (defpackage "TERM"
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[1605] | 23 | (:use :cl :monom :ring)
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[2845] | 24 | (:export "TERM"
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| 25 | "MAKE-TERM-VARIABLE"
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| 26 | )
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[2702] | 27 | (:documentation "This package implements class TERM. A term is a
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| 28 | product of a scalar and powers of some variables, such as
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| 29 | 5*X^2*Y^3. The part of the term without the coefficient is a monomial
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| 30 | X^2*Y^3, which is represented by class MONOM, provided by the :MONOM
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| 31 | package. In this implementation, a TERM specializes MONOL. Also, a
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| 32 | monomial can be considered a TERM whose coefficient is the unit
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| 33 | element (1) of the underlying ring. The generic method CHANGE-CLASS
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| 34 | can be used to convert between a MONOM and a TERM, observing this
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[2703] | 35 | convention."))
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[78] | 36 |
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[420] | 37 | (in-package :term)
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| 38 |
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[1926] | 39 | (proclaim '(optimize (speed 3) (space 0) (safety 0) (debug 0)))
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| 40 |
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[3132] | 41 | (defclass term (monom scalar)
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[3140] | 42 | ()
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[3147] | 43 | (:default-initargs :dimension nil :exponents nil :coeff nil)
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[3142] | 44 | (:documentation "Implements a term, i.e. a product of a scalar
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[2704] | 45 | and powers of some variables, such as 5*X^2*Y^3."))
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[766] | 46 |
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[2275] | 47 | (defmethod print-object ((self term) stream)
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[3160] | 48 | (with-slots (dimension exponents coeff)
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| 49 | self
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| 50 | (format stream "#<TERM DIMENSION=~A EXPONENTS=~A COEFF=~A>"
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| 51 | dimension
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| 52 | exponents
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| 53 | coeff))
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| 54 | self)
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| 55 |
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[2275] | 56 |
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[3151] | 57 | (defmethod r-equalp ((term1 term) (term2 term))
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| 58 | (and (r-equalp (scalar-coeff term1) (scalar-coeff term2))
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[3152] | 59 | (= (monom-dimension term1) (monom-dimension term2))
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| 60 | (equalp (monom-exponents term1) (monom-exponents term2))))
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[3151] | 61 |
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| 62 |
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[3141] | 63 | #|
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[2339] | 64 | (defmethod shared-initialize ((self term) slot-names
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| 65 | &rest
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[2395] | 66 | initargs
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[2339] | 67 | &key
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[2377] | 68 | coeff
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| 69 | &allow-other-keys)
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[2395] | 70 | (declare (ignore initargs))
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[2385] | 71 | (if (eq slot-names t) (setf slot-names '(coeff)))
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[2378] | 72 | (dolist (slot-name slot-names)
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| 73 | (case slot-name
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| 74 | (coeff
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[2391] | 75 | (setf (slot-value self 'coeff) coeff)))))
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[3141] | 76 | |#
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[2342] | 77 |
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[3158] | 78 | (defmethod update-instance-for-different-class ((old monom) (new term)
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| 79 | &rest initargs &key &allow-other-keys)
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[2905] | 80 | ;; Changing an instance of class MONOM to class TERM may also
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| 81 | ;; happen when OLD is an instance of TERM, in which case the
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| 82 | ;; value of the coefficient should be preserved.
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[3159] | 83 | (setf initargs (list* :coeff 1 initargs))
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| 84 | (call-next-method))
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[2377] | 85 |
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[2288] | 86 | #|
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[2189] | 87 | (defun make-term-variable (nvars pos
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[2021] | 88 | &optional
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| 89 | (power 1)
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[2189] | 90 | (coeff 1))
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[400] | 91 | "Construct a term in the polynomial ring RING[X[0],X[1],X[2],...X[NVARS-1]]
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[399] | 92 | over the ring RING which represents a single variable. It assumes
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| 93 | number of variables NVARS and the variable is at position
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| 94 | POS. Optionally, the variable may appear raised to power POWER.
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| 95 | Optionally, the term may appear with an arbitrary coefficient, which
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| 96 | defaults to the unit of the RING."
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[2189] | 97 | (declare (type fixnum nvars pos))
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[1959] | 98 | (make-term :monom (make-monom-variable nvars pos power)
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| 99 | :coeff coeff))
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[51] | 100 |
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[2352] | 101 | |#
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| 102 |
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[2946] | 103 | (defmethod multiply-by :before ((self term) (other term))
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[2833] | 104 | "Destructively multiply terms SELF and OTHER and store the result into SELF.
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[2805] | 105 | It returns SELF."
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[3143] | 106 | (setf (scalar-coeff self) (multiply-by (scalar-coeff self) (scalar-coeff other))))
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[2477] | 107 |
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[3031] | 108 | (defmethod left-tensor-product-by ((self term) (other term))
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[3143] | 109 | (setf (scalar-coeff self) (multiply-by (scalar-coeff self) (scalar-coeff other)))
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[3031] | 110 | (call-next-method))
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[3027] | 111 |
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[3038] | 112 | (defmethod right-tensor-product-by ((self term) (other term))
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[3143] | 113 | (setf (scalar-coeff self) (multiply-by (scalar-coeff self) (scalar-coeff other)))
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[3038] | 114 | (call-next-method))
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| 115 |
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[3059] | 116 | (defmethod left-tensor-product-by ((self term) (other monom))
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| 117 | (call-next-method))
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| 118 |
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| 119 | (defmethod right-tensor-product-by ((self term) (other monom))
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| 120 | (call-next-method))
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| 121 |
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[2832] | 122 | (defmethod divide-by ((self term) (other term))
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[2833] | 123 | "Destructively divide term SELF by OTHER and store the result into SELF.
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[2832] | 124 | It returns SELF."
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[3143] | 125 | (setf (scalar-coeff self) (divide-by (scalar-coeff self) (scalar-coeff other)))
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[2832] | 126 | (call-next-method))
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| 127 |
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[2685] | 128 | (defmethod unary-minus ((self term))
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[3135] | 129 | (setf (scalar-coeff self) (unary-minus (scalar-coeff self)))
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[2685] | 130 | self)
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| 131 |
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[2938] | 132 | (defmethod r* ((term1 term) (term2 term))
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| 133 | "Non-destructively multiply TERM1 by TERM2."
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[2967] | 134 | (multiply-by (copy-instance term1) (copy-instance term2)))
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[2938] | 135 |
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[2942] | 136 | (defmethod r-zerop ((self term))
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[3135] | 137 | (r-zerop (scalar-coeff self)))
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[2938] | 138 |
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[2352] | 139 | #|
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[1147] | 140 |
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| 141 | (defun term->cons (term)
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[1154] | 142 | "A human-readable representation of a term as a cons (MONOM . COEFF)."
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[1902] | 143 | (declare (type term term))
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[3135] | 144 | (cons (monom->list (term-monom term)) (scalar-coeff term)))
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[1147] | 145 |
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[2288] | 146 | |#
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