X-Git-Url: https://www.ginac.de/ginac.git//ginac.git?a=blobdiff_plain;f=ginac%2Fexpairseq.h;h=665daed8325b10d2d06d7fe9f0c3c9c8ca954173;hb=b05dd71f9a2e70fe1e4978b455cc39bf16952bcc;hp=d9cc0b31140c1bd955686743e307f3d7c4a084c4;hpb=e58227e1112f989f3b5417e497a61d53fc2971fa;p=ginac.git diff --git a/ginac/expairseq.h b/ginac/expairseq.h index d9cc0b31..665daed8 100644 --- a/ginac/expairseq.h +++ b/ginac/expairseq.h @@ -25,70 +25,65 @@ #include #include - // CINT needs to work properly with and #include #include "expair.h" -#ifndef NO_NAMESPACE_GINAC namespace GiNaC { -#endif // ndef NO_NAMESPACE_GINAC - -//#define EXPAIRSEQ_USE_HASHTAB - -typedef std::vector epvector; -typedef epvector::iterator epviter; - -inline void iter_swap(epvector::iterator it1, epvector::iterator it2) -{ - (*it1).rest.swap((*it2).rest); - (*it1).coeff.swap((*it2).coeff); -} -typedef epvector::iterator epp; -typedef std::list epplist; -typedef std::vector epplistvector; +/** 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 epvector; ///< expair-vector +typedef epvector::iterator epviter; ///< expair-vector iterator +typedef epvector::iterator epp; ///< expair-vector pointer +typedef std::list epplist; ///< list of expair-vector pointers +typedef std::vector epplistvector; ///< vector of epplist /** 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. (Incidentally, Maple does it - * the same way.) */ + * 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) + GINAC_DECLARE_REGISTERED_CLASS_NO_CTORS(expairseq, basic) // member functions - // default constructor, destructor, copy constructor assignment operator and helpers + // default ctor, dtor, copy ctor assignment operator and helpers public: expairseq() : basic(TINFO_expairseq) -#ifdef EXPAIRSEQ_USE_HASHTAB +#if EXPAIRSEQ_USE_HASHTAB , hashtabsize(0) -#endif // def EXPAIRSEQ_USE_HASHTAB - { - } - ~expairseq() - { - destroy(0); - } +#endif // EXPAIRSEQ_USE_HASHTAB + { } + ~expairseq() { destroy(false); } expairseq(const expairseq & other); const expairseq & operator=(const expairseq & other); protected: void copy(const expairseq & other); - void destroy(bool call_parent) - { - if (call_parent) basic::destroy(call_parent); - }; - - // other constructors + void destroy(bool call_parent); + // other ctors public: expairseq(const ex & lh, const ex & rh); expairseq(const exvector & v); expairseq(const epvector & v, const ex & oc); expairseq(epvector * vp, const ex & oc); // vp will be deleted - + // functions overriding virtual functions from bases classes public: basic * duplicate() const; @@ -111,7 +106,7 @@ protected: unsigned return_type(void) const; unsigned calchash(void) 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; @@ -145,11 +140,9 @@ protected: void construct_from_epvector(const epvector & v); void make_flat(const exvector & v); void make_flat(const epvector & v); - epvector * bubblesort(epvector::iterator itbegin, epvector::iterator itend); - epvector * mergesort(epvector::iterator itbegin, epvector::iterator itend); void canonicalize(void); void combine_same_terms_sorted_seq(void); -#ifdef EXPAIRSEQ_USE_HASHTAB +#if EXPAIRSEQ_USE_HASHTAB void combine_same_terms(void); unsigned calc_hashtabsize(unsigned sz) const; unsigned calc_hashindex(const ex & e) const; @@ -169,7 +162,7 @@ protected: bool has_coeff_0(void) const; void add_numerics_to_hashtab(epvector::iterator first_numeric, epvector::const_iterator last_non_zero); -#endif // def EXPAIRSEQ_USE_HASHTAB +#endif // EXPAIRSEQ_USE_HASHTAB bool is_canonical() const; epvector * expandchildren(unsigned options) const; epvector * evalchildren(int level) const; @@ -184,14 +177,14 @@ protected: epvector seq; ex overall_coeff; static unsigned precedence; -#ifdef EXPAIRSEQ_USE_HASHTAB +#if EXPAIRSEQ_USE_HASHTAB epplistvector hashtab; unsigned hashtabsize; unsigned hashmask; static unsigned maxhashtabsize; static unsigned minhashtabsize; static unsigned hashtabfactor; -#endif // def EXPAIRSEQ_USE_HASHTAB +#endif // EXPAIRSEQ_USE_HASHTAB }; // utility functions @@ -200,8 +193,6 @@ inline const expairseq &ex_to_expairseq(const ex &e) return static_cast(*e.bp); } -#ifndef NO_NAMESPACE_GINAC } // namespace GiNaC -#endif // ndef NO_NAMESPACE_GINAC #endif // ndef __GINAC_EXPAIRSEQ_H__