[975db18] | 1 | // -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- |
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| 2 | /*****************************************************************************\ |
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[fea494] | 3 | * Computer Algebra System SINGULAR |
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[975db18] | 4 | \*****************************************************************************/ |
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| 5 | /** @file PolyEnumerator.h |
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[fea494] | 6 | * |
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[975db18] | 7 | * Concrete implementation of enumerators over polynomials |
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| 8 | * |
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| 9 | * @author Oleksandr Motsak |
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| 10 | * |
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| 11 | * |
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| 12 | **/ |
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| 13 | /*****************************************************************************/ |
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| 14 | |
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| 15 | #ifndef POLYENUMERATOR_H |
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| 16 | #define POLYENUMERATOR_H |
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| 17 | |
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| 18 | // include basic definitions |
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[aadd638] | 19 | #include "coeffs/Enumerator.h" |
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| 20 | #include "polys/monomials/monomials.h" |
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| 21 | #include "reporter/reporter.h" // for assume etc. |
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[975db18] | 22 | |
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| 23 | /** @class CBasePolyEnumerator |
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[fea494] | 24 | * |
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[9952bd] | 25 | * Base polynomial enumerator for simple iteration over terms of polynomials. |
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[975db18] | 26 | * |
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[9952bd] | 27 | * Note that the first element desn't exist directly after Reset() call. |
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[fea494] | 28 | * |
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[9952bd] | 29 | * The class doesn't inherit from IAccessor and thus doesn't override Current(). |
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[975db18] | 30 | * |
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| 31 | * @sa IBaseEnumerator, @sa CPolyCoeffsEnumerator |
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| 32 | */ |
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| 33 | class CBasePolyEnumerator: public virtual IBaseEnumerator |
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| 34 | { |
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[dc79bd] | 35 | template <class T> |
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| 36 | friend class CRecursivePolyCoeffsEnumerator; |
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[975db18] | 37 | private: |
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[dc79bd] | 38 | poly m_poly; ///< essentially immutable original iterable object |
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[fea494] | 39 | |
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[9952bd] | 40 | static const spolyrec m_prevposition_struct; ///< tag for "-1" position |
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[975db18] | 41 | |
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| 42 | protected: |
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[9952bd] | 43 | poly m_position; ///< current position in the iterable object |
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| 44 | |
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[dc79bd] | 45 | public: |
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[9952bd] | 46 | virtual bool IsValid() const |
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[975db18] | 47 | { |
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[9952bd] | 48 | // not -1 or past the end position? |
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| 49 | return (m_position != NULL) && (m_position != &m_prevposition_struct); |
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| 50 | } |
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[dc79bd] | 51 | |
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| 52 | |
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| 53 | /// Reset this polynomial Enumerator with a different input polynomial |
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| 54 | void Reset(poly p) |
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| 55 | { |
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| 56 | m_poly = p; |
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| 57 | m_position = const_cast<poly>(&m_prevposition_struct); |
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[fea494] | 58 | assume( !IsValid() ); |
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[dc79bd] | 59 | } |
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| 60 | |
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| 61 | /// This enumerator is an empty polynomial by default |
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| 62 | CBasePolyEnumerator(poly p = NULL): |
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[9952bd] | 63 | IBaseEnumerator(), m_poly(p), m_position(const_cast<poly>(&m_prevposition_struct)) |
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| 64 | { |
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[fea494] | 65 | assume( !IsValid() ); |
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[9952bd] | 66 | } |
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[fea494] | 67 | |
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[975db18] | 68 | /// Sets the position marker to the leading term. |
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[9952bd] | 69 | virtual void Reset() |
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| 70 | { |
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| 71 | m_position = const_cast<poly>(&m_prevposition_struct); |
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[fea494] | 72 | assume( !IsValid() ); |
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[9952bd] | 73 | } |
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[975db18] | 74 | |
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[dc79bd] | 75 | |
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[975db18] | 76 | /// Advances the position to the next term of the polynomial. |
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| 77 | /// returns true if the position marker was successfully advanced to the |
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[9952bd] | 78 | /// next term which can be used; |
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[975db18] | 79 | /// false if the position marker has passed the end of the |
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| 80 | /// polynomial. |
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| 81 | virtual bool MoveNext() |
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| 82 | { |
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| 83 | assume( m_position != NULL ); |
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[9952bd] | 84 | |
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| 85 | { |
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| 86 | const poly p_next = pNext(m_position); |
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| 87 | |
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| 88 | if (p_next != NULL) // not the last term? |
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| 89 | { |
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| 90 | m_position = p_next; |
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| 91 | assume( IsValid() ); |
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| 92 | return true; |
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| 93 | } |
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| 94 | } |
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[fea494] | 95 | |
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[9952bd] | 96 | if (m_position == &m_prevposition_struct) // -1 position? |
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| 97 | { |
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| 98 | assume( !IsValid() ); |
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| 99 | m_position = m_poly; |
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| 100 | return (m_position != NULL); |
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| 101 | } |
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| 102 | |
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| 103 | // else: past the end (or an empty polynomial) |
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| 104 | m_position = NULL; |
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| 105 | assume( !IsValid() ); |
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| 106 | return false; |
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[975db18] | 107 | } |
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| 108 | }; |
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| 109 | |
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| 110 | |
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| 111 | /// This is the interface we use in coeffs.h for ClearDenominators and |
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| 112 | /// ClearContent. |
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| 113 | typedef IEnumerator<number> IPolyCoeffsEnumerator; |
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| 114 | |
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| 115 | /** @class CPolyCoeffsEnumerator |
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[fea494] | 116 | * |
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[975db18] | 117 | * This is a polynomial enumerator for simple iteration over |
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[9952bd] | 118 | * coefficients of polynomials. |
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[fea494] | 119 | * |
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[975db18] | 120 | * It is required to inherit this class from IEnumerator<number> for |
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| 121 | * its use in coeffs and implement IAccessor<number> interface. |
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| 122 | * |
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| 123 | * Note also the virtual multiple inheritance due to the diamond |
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| 124 | * problem of inheriting both CBasePolyEnumerator and IEnumerator<T> |
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| 125 | * from IBaseEnumerator. |
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| 126 | * |
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| 127 | * @sa CBasePolyEnumerator, @sa IEnumerator |
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| 128 | */ |
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| 129 | class CPolyCoeffsEnumerator: public CBasePolyEnumerator, public virtual IPolyCoeffsEnumerator |
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| 130 | { |
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| 131 | public: |
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[dc79bd] | 132 | CPolyCoeffsEnumerator(poly p): CBasePolyEnumerator(p) {} |
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[fea494] | 133 | |
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[975db18] | 134 | /// Gets the current element in the collection (read and write). |
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| 135 | virtual IPolyCoeffsEnumerator::reference Current() |
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| 136 | { |
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[9952bd] | 137 | assume( IsValid() ); |
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[fea494] | 138 | return pGetCoeff(m_position); |
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[975db18] | 139 | } |
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| 140 | |
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| 141 | /// Gets the current element in the collection (read only). |
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| 142 | virtual IPolyCoeffsEnumerator::const_reference Current() const |
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| 143 | { |
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[9952bd] | 144 | assume( IsValid() ); |
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[975db18] | 145 | return pGetCoeff(m_position); |
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| 146 | } |
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| 147 | }; |
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| 148 | |
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[dc79bd] | 149 | |
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| 150 | struct NAConverter |
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| 151 | { |
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| 152 | static inline poly convert(const number& n) |
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| 153 | { |
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| 154 | // suitable for alg. ext. numbers that are just polys actually |
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| 155 | return (poly)n; |
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| 156 | } |
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| 157 | }; |
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| 158 | |
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| 159 | /// go into polynomials over an alg. extension recursively |
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| 160 | template <class ConverterPolicy> |
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| 161 | class CRecursivePolyCoeffsEnumerator: public IPolyCoeffsEnumerator |
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| 162 | { |
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| 163 | private: |
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| 164 | IPolyCoeffsEnumerator& m_global_enumerator; ///< iterates the input polynomial |
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| 165 | CBasePolyEnumerator m_local_enumerator; ///< iterates the current coeff. of m_global_enumerator |
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| 166 | |
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| 167 | protected: |
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| 168 | virtual bool IsValid() const |
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| 169 | { |
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| 170 | return m_global_enumerator.IsValid() && m_local_enumerator.IsValid(); |
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[fea494] | 171 | } |
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| 172 | |
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[dc79bd] | 173 | public: |
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[fea494] | 174 | |
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[dc79bd] | 175 | /// NOTE: carefull: don't destruct the input enumerator before doing it with this one... |
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| 176 | /// this also changes the original IPolyCoeffsEnumerator& itr! |
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| 177 | CRecursivePolyCoeffsEnumerator(IPolyCoeffsEnumerator& itr): m_global_enumerator(itr), m_local_enumerator(NULL) {} |
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| 178 | |
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| 179 | virtual bool MoveNext() |
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| 180 | { |
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| 181 | if( m_local_enumerator.MoveNext() ) |
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| 182 | return true; |
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| 183 | |
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| 184 | if( !m_global_enumerator.MoveNext() ) // at the end of the main input polynomial? |
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| 185 | return false; |
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| 186 | |
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| 187 | // TODO: make the following changeable (metaprogramming: use policy?), |
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| 188 | // leave the following as default option... |
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| 189 | poly p = ConverterPolicy::convert(m_global_enumerator.Current()); // Assumes that these numbers are just polynomials! |
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| 190 | assume( p != NULL ); |
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| 191 | |
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| 192 | // the followig actually needs CPolyCoeffsEnumerator |
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| 193 | m_local_enumerator.Reset( p ); // -1 position in p :: to be skipped now! |
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| 194 | |
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| 195 | if( m_local_enumerator.MoveNext() ) // should be true |
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| 196 | return true; |
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| 197 | |
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| 198 | assume( FALSE ); return MoveNext(); // this should not happen as p should be non-zero, but just in case... |
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| 199 | } |
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[fea494] | 200 | |
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[dc79bd] | 201 | virtual void Reset() |
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| 202 | { |
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| 203 | m_global_enumerator.Reset(); |
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| 204 | m_local_enumerator.Reset(NULL); |
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| 205 | } |
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| 206 | |
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| 207 | /// Gets the current element in the collection (read and write). |
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| 208 | virtual IPolyCoeffsEnumerator::reference Current() |
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| 209 | { |
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| 210 | assume( IsValid() ); |
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| 211 | return pGetCoeff(m_local_enumerator.m_position); |
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| 212 | } |
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| 213 | |
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| 214 | /// Gets the current element in the collection (read only). |
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| 215 | virtual IPolyCoeffsEnumerator::const_reference Current() const |
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| 216 | { |
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| 217 | assume( IsValid() ); |
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| 218 | return pGetCoeff(m_local_enumerator.m_position); |
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| 219 | } |
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| 220 | }; |
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| 221 | |
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| 222 | |
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[fea494] | 223 | #endif |
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[975db18] | 224 | /* #ifndef POLYENUMERATOR_H */ |
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| 225 | |
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| 226 | // Vi-modeline: vim: filetype=c:syntax:shiftwidth=2:tabstop=8:textwidth=0:expandtab |
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| 227 | |
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