3 * Interface to sequences of expression pairs. */
6 * GiNaC Copyright (C) 1999-2001 Johannes Gutenberg University Mainz, Germany
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
23 #ifndef __GINAC_EXPAIRSEQ_H__
24 #define __GINAC_EXPAIRSEQ_H__
28 // CINT needs <algorithm> to work properly with <vector> and <list>
35 /** Using hash tables can potentially enhance the asymptotic behaviour of
36 * combining n terms into one large sum (or n terms into one large product)
37 * from O(n*log(n)) to about O(n). There are, however, several drawbacks.
38 * The constant in front of O(n) is quite large, when copying such an object
39 * one also has to copy the has table, comparison is quite expensive because
40 * there is no ordering any more, it doesn't help at all when combining two
41 * expairseqs because due to the presorted nature the behaviour would be
42 * O(n) anyways, the code is quite messy, etc, etc. The code is here as
43 * an example for following generations to tinker with. */
44 #define EXPAIRSEQ_USE_HASHTAB 0
46 typedef std::vector<expair> epvector; ///< expair-vector
47 typedef epvector::iterator epp; ///< expair-vector pointer
48 typedef std::list<epp> epplist; ///< list of expair-vector pointers
49 typedef std::vector<epplist> epplistvector; ///< vector of epplist
51 /** A sequence of class expair.
52 * This is used for time-critical classes like sums and products of terms
53 * since handling a list of coeff and rest is much faster than handling a
54 * list of products or powers, respectively. (Not incidentally, Maple does it
55 * the same way, maybe others too.) The semantics is (at least) twofold:
56 * one for addition and one for multiplication and several methods have to
57 * be overridden by derived classes to reflect the change in semantics.
58 * However, most functionality turns out to be shared between addition and
59 * multiplication, which is the reason why there is this base class. */
60 class expairseq : public basic
62 GINAC_DECLARE_REGISTERED_CLASS_NO_CTORS(expairseq, basic)
66 // default ctor, dtor, copy ctor assignment operator and helpers
68 expairseq() : basic(TINFO_expairseq)
69 #if EXPAIRSEQ_USE_HASHTAB
71 #endif // EXPAIRSEQ_USE_HASHTAB
73 ~expairseq() { destroy(false); }
74 expairseq(const expairseq & other);
75 const expairseq & operator=(const expairseq & other);
77 void copy(const expairseq & other);
78 void destroy(bool call_parent);
81 expairseq(const ex & lh, const ex & rh);
82 expairseq(const exvector & v);
83 expairseq(const epvector & v, const ex & oc);
84 expairseq(epvector * vp, const ex & oc); // vp will be deleted
86 // functions overriding virtual functions from base classes
88 basic * duplicate() const;
89 void print(const print_context & c, unsigned level = 0) const;
90 unsigned precedence(void) const {return 10;}
91 bool info(unsigned inf) const;
92 unsigned nops() const;
95 ex map(map_function & f) const;
96 ex eval(int level=0) const;
97 ex to_rational(lst &repl_lst) const;
98 bool match(const ex & pattern, lst & repl_lst) const;
99 ex subs(const lst & ls, const lst & lr, bool no_pattern = false) const;
101 int compare_same_type(const basic & other) const;
102 bool is_equal_same_type(const basic & other) const;
103 unsigned return_type(void) const;
104 unsigned calchash(void) const;
105 ex expand(unsigned options=0) const;
107 // new virtual functions which can be overridden by derived classes
109 virtual ex thisexpairseq(const epvector & v, const ex & oc) const;
110 virtual ex thisexpairseq(epvector * vp, const ex & oc) const;
111 virtual void printseq(const print_context & c, char delim,
112 unsigned this_precedence,
113 unsigned upper_precedence) const;
114 virtual void printpair(const print_context & c, const expair & p,
115 unsigned upper_precedence) const;
116 virtual expair split_ex_to_pair(const ex & e) const;
117 virtual expair combine_ex_with_coeff_to_pair(const ex & e,
119 virtual expair combine_pair_with_coeff_to_pair(const expair & p,
121 virtual ex recombine_pair_to_ex(const expair & p) const;
122 virtual bool expair_needs_further_processing(epp it);
123 virtual ex default_overall_coeff(void) const;
124 virtual void combine_overall_coeff(const ex & c);
125 virtual void combine_overall_coeff(const ex & c1, const ex & c2);
126 virtual bool can_make_flat(const expair & p) const;
128 // non-virtual functions in this class
130 void construct_from_2_ex_via_exvector(const ex & lh, const ex & rh);
131 void construct_from_2_ex(const ex & lh, const ex & rh);
132 void construct_from_2_expairseq(const expairseq & s1,
133 const expairseq & s2);
134 void construct_from_expairseq_ex(const expairseq & s,
136 void construct_from_exvector(const exvector & v);
137 void construct_from_epvector(const epvector & v);
138 void make_flat(const exvector & v);
139 void make_flat(const epvector & v);
140 void canonicalize(void);
141 void combine_same_terms_sorted_seq(void);
142 #if EXPAIRSEQ_USE_HASHTAB
143 void combine_same_terms(void);
144 unsigned calc_hashtabsize(unsigned sz) const;
145 unsigned calc_hashindex(const ex & e) const;
146 void shrink_hashtab(void);
147 void remove_hashtab_entry(epvector::const_iterator element);
148 void move_hashtab_entry(epvector::const_iterator oldpos,
149 epvector::iterator newpos);
150 void sorted_insert(epplist & eppl, epvector::const_iterator elem);
151 void build_hashtab_and_combine(epvector::iterator & first_numeric,
152 epvector::iterator & last_non_zero,
153 vector<bool> & touched,
154 unsigned & number_of_zeroes);
155 void drop_coeff_0_terms(epvector::iterator & first_numeric,
156 epvector::iterator & last_non_zero,
157 vector<bool> & touched,
158 unsigned & number_of_zeroes);
159 bool has_coeff_0(void) const;
160 void add_numerics_to_hashtab(epvector::iterator first_numeric,
161 epvector::const_iterator last_non_zero);
162 #endif // EXPAIRSEQ_USE_HASHTAB
163 bool is_canonical() const;
164 epvector * expandchildren(unsigned options) const;
165 epvector * evalchildren(int level) const;
166 epvector * subschildren(const lst & ls, const lst & lr, bool no_pattern = false) const;
173 #if EXPAIRSEQ_USE_HASHTAB
174 epplistvector hashtab;
175 unsigned hashtabsize;
177 static unsigned maxhashtabsize;
178 static unsigned minhashtabsize;
179 static unsigned hashtabfactor;
180 #endif // EXPAIRSEQ_USE_HASHTAB
185 /** Return the expairseq object handled by an ex. Deprecated: use ex_to<expairseq>().
186 * This is unsafe: you need to check the type first. */
187 inline const expairseq &ex_to_expairseq(const ex &e)
189 return static_cast<const expairseq &>(*e.bp);
192 /** Specialization of is_exactly_a<expairseq>(obj) for expairseq objects. */
193 template<> inline bool is_exactly_a<expairseq>(const basic & obj)
195 return obj.tinfo()==TINFO_expairseq;
200 #endif // ndef __GINAC_EXPAIRSEQ_H__