/** @file expairseq.h
*
* Interface to sequences of expression pairs. */
/*
* GiNaC Copyright (C) 1999-2007 Johannes Gutenberg University Mainz, Germany
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef __GINAC_EXPAIRSEQ_H__
#define __GINAC_EXPAIRSEQ_H__
#include <vector>
#include <list>
#include <memory>
// CINT needs <algorithm> to work properly with <vector> and <list>
#include <algorithm>
#include "expair.h"
namespace GiNaC {
/** Using hash tables can potentially enhance the asymptotic behaviour of
* combining n terms into one large sum (or n terms into one large product)
* from O(n*log(n)) to about O(n). There are, however, several drawbacks.
* The constant in front of O(n) is quite large, when copying such an object
* one also has to copy the has table, comparison is quite expensive because
* there is no ordering any more, it doesn't help at all when combining two
* expairseqs because due to the presorted nature the behaviour would be
* O(n) anyways, the code is quite messy, etc, etc. The code is here as
* an example for following generations to tinker with. */
#define EXPAIRSEQ_USE_HASHTAB 0
typedef std::vector<expair> epvector; ///< expair-vector
typedef epvector::iterator epp; ///< expair-vector pointer
typedef std::list<epp> epplist; ///< list of expair-vector pointers
typedef std::vector<epplist> epplistvector; ///< vector of epplist
/** Complex conjugate every element of an epvector. Returns zero if this
* does not change anything. */
epvector* conjugateepvector(const epvector&);
/** A sequence of class expair.
* This is used for time-critical classes like sums and products of terms
* since handling a list of coeff and rest is much faster than handling a
* list of products or powers, respectively. (Not incidentally, Maple does it
* the same way, maybe others too.) The semantics is (at least) twofold:
* one for addition and one for multiplication and several methods have to
* be overridden by derived classes to reflect the change in semantics.
* However, most functionality turns out to be shared between addition and
* multiplication, which is the reason why there is this base class. */
class expairseq : public basic
{
GINAC_DECLARE_REGISTERED_CLASS(expairseq, basic)
// other constructors
public:
expairseq(const ex & lh, const ex & rh);
expairseq(const exvector & v);
expairseq(const epvector & v, const ex & oc);
expairseq(std::auto_ptr<epvector>, const ex & oc);
// functions overriding virtual functions from base classes
public:
unsigned precedence() const {return 10;}
bool info(unsigned inf) const;
size_t nops() const;
ex op(size_t i) const;
ex map(map_function & f) const;
ex eval(int level=0) const;
ex to_rational(exmap & repl) const;
ex to_polynomial(exmap & repl) const;
bool match(const ex & pattern, lst & repl_lst) const;
ex subs(const exmap & m, unsigned options = 0) const;
ex conjugate() const;
protected:
bool is_equal_same_type(const basic & other) const;
unsigned return_type() const;
unsigned calchash() const;
ex expand(unsigned options=0) const;
// new virtual functions which can be overridden by derived classes
protected:
virtual ex thisexpairseq(const epvector & v, const ex & oc) const;
virtual ex thisexpairseq(std::auto_ptr<epvector> vp, const ex & oc) const;
virtual void printseq(const print_context & c, char delim,
unsigned this_precedence,
unsigned upper_precedence) const;
virtual void printpair(const print_context & c, const expair & p,
unsigned upper_precedence) const;
virtual expair split_ex_to_pair(const ex & e) const;
virtual expair combine_ex_with_coeff_to_pair(const ex & e,
const ex & c) const;
virtual expair combine_pair_with_coeff_to_pair(const expair & p,
const ex & c) const;
virtual ex recombine_pair_to_ex(const expair & p) const;
virtual bool expair_needs_further_processing(epp it);
virtual ex default_overall_coeff() const;
virtual void combine_overall_coeff(const ex & c);
virtual void combine_overall_coeff(const ex & c1, const ex & c2);
virtual bool can_make_flat(const expair & p) const;
// non-virtual functions in this class
protected:
void do_print(const print_context & c, unsigned level) const;
void do_print_tree(const print_tree & c, unsigned level) const;
void construct_from_2_ex_via_exvector(const ex & lh, const ex & rh);
void construct_from_2_ex(const ex & lh, const ex & rh);
void construct_from_2_expairseq(const expairseq & s1,
const expairseq & s2);
void construct_from_expairseq_ex(const expairseq & s,
const ex & e);
void construct_from_exvector(const exvector & v);
void construct_from_epvector(const epvector & v);
void make_flat(const exvector & v);
void make_flat(const epvector & v);
void canonicalize();
void combine_same_terms_sorted_seq();
#if EXPAIRSEQ_USE_HASHTAB
void combine_same_terms();
unsigned calc_hashtabsize(unsigned sz) const;
unsigned calc_hashindex(const ex & e) const;
void shrink_hashtab();
void remove_hashtab_entry(epvector::const_iterator element);
void move_hashtab_entry(epvector::const_iterator oldpos,
epvector::iterator newpos);
void sorted_insert(epplist & eppl, epvector::const_iterator elem);
void build_hashtab_and_combine(epvector::iterator & first_numeric,
epvector::iterator & last_non_zero,
vector<bool> & touched,
unsigned & number_of_zeroes);
void drop_coeff_0_terms(epvector::iterator & first_numeric,
epvector::iterator & last_non_zero,
vector<bool> & touched,
unsigned & number_of_zeroes);
bool has_coeff_0() const;
void add_numerics_to_hashtab(epvector::iterator first_numeric,
epvector::const_iterator last_non_zero);
#endif // EXPAIRSEQ_USE_HASHTAB
bool is_canonical() const;
std::auto_ptr<epvector> expandchildren(unsigned options) const;
std::auto_ptr<epvector> evalchildren(int level) const;
std::auto_ptr<epvector> subschildren(const exmap & m, unsigned options = 0) const;
// member variables
protected:
epvector seq;
ex overall_coeff;
#if EXPAIRSEQ_USE_HASHTAB
epplistvector hashtab;
unsigned hashtabsize;
unsigned hashmask;
static unsigned maxhashtabsize;
static unsigned minhashtabsize;
static unsigned hashtabfactor;
#endif // EXPAIRSEQ_USE_HASHTAB
};
// utility functions
/** Specialization of is_exactly_a<expairseq>(obj) for expairseq objects. */
template<> inline bool is_exactly_a<expairseq>(const basic & obj)
{
return obj.tinfo()==TINFO_expairseq;
}
} // namespace GiNaC
#endif // ndef __GINAC_EXPAIRSEQ_H__
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