| 1 | (in-package "POLYNOMIAL")
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| 2 |
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| 3 | (defgeneric static-sugar (object)
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| 4 | (:documentation "Return statically calculated sugar of object OBJECT. That is,
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| 5 | the sugar value which does not assume that the object is a result of any prior calculations.")
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| 6 | (:method ((object monom))
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| 7 | "Static sugar of a monom OBJECT is simply the total degree."
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| 8 | (total-degree object))
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| 9 | (:method ((object poly))
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| 10 | "Static sugar of a poly OBJECT is the maximum sugar of its terms."
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| 11 | (with-slots (termlist)
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| 12 | object
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| 13 | (loop for trm in termlist maximize (static-sugar trm)))))
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| 14 |
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| 15 | (defclass sugar ()
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| 16 | ((value :initarg :value :initform -1 :accessor sugar-value :type fixnum))
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| 17 | (:documentation "Sugar is a quantity added to various objects, such as monomials, terms and polynomials."))
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| 18 |
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| 19 | (defclass monom-with-sugar (monom sugar) ())
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| 20 |
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| 21 | (defmethod print-object ((self monom-with-sugar) stream)
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| 22 | (print-unreadable-object (self stream :type t :identity t)
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| 23 | (with-accessors ((exponents monom-exponents) (value sugar-value))
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| 24 | self
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| 25 | (format stream "EXPONENTS=~A SUGAR=~A"
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| 26 | exponents value))))
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| 27 |
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| 28 |
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| 29 | (defmethod shared-initialize :after ((self monom-with-sugar) slot-names &rest initargs &key)
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| 30 | "Initialize sugar value based on the exponents."
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| 31 | (declare (ignore slot-names initargs))
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| 32 | (setf (slot-value self 'value) (static-sugar self)))
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| 33 |
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| 34 | (defmethod multiply-by :after ((self sugar) (other sugar))
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| 35 | (with-slots (value)
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| 36 | self
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| 37 | (with-slots ((other-value value))
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| 38 | other
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| 39 | (incf value other-value)))
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| 40 | self)
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| 41 |
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| 42 | (defclass term-with-sugar (term sugar) ())
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| 43 |
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| 44 | (defmethod print-object ((self term-with-sugar) stream)
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| 45 | (print-unreadable-object (self stream :type t :identity t)
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| 46 | (with-accessors ((exponents monom-exponents) (value sugar-value) (coeff term-coeff))
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| 47 | self
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| 48 | (format stream "EXPONENTS=~A COEFF=~A SUGAR=~A"
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| 49 | exponents coeff value))))
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| 50 |
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| 51 | (defclass poly-with-sugar (poly sugar) ())
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| 52 |
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| 53 | (defmethod shared-initialize :after ((self poly-with-sugar) slot-names &rest initargs &key)
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| 54 | "Initialize sugar to its static value, which is the maximum of sugar values of the terms."
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| 55 | (declare (ignore slot-names initargs))
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| 56 | (setf (slot-value self 'value) (static-sugar self)))
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