#include <vector>
#include <list>
-
// CINT needs <algorithm> to work properly with <vector> and <list>
#include <algorithm>
#include "expair.h"
-#ifndef NO_NAMESPACE_GINAC
namespace GiNaC {
-#endif // ndef NO_NAMESPACE_GINAC
-
-//#define EXPAIRSEQ_USE_HASHTAB
-
-typedef std::vector<expair> 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<epp> epplist;
-typedef std::vector<epplist> 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<expair> epvector; ///< expair-vector
+typedef epvector::iterator epviter; ///< expair-vector iterator
+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
/** 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_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;
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;
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;
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;
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
return static_cast<const expairseq &>(*e.bp);
}
-#ifndef NO_NAMESPACE_GINAC
} // namespace GiNaC
-#endif // ndef NO_NAMESPACE_GINAC
#endif // ndef __GINAC_EXPAIRSEQ_H__
git://www.ginac.de / ginac.git / blobdiff