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