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// Copyright 1996 Michael E. Stillman
// This should probably be done by:
// (a) making a type FREEMODULETYPE, that FreeModule, and res_poly
// both can inherit from: but this is a bit of a kludge...
// (b) making a vector type with a next and coeff field, that
// is then inherited by vecterm, resterm.
// Redefine:
// FREEMODULETYPE
// routines that should be implemented in this class:
// add_to, compare, get_ring, remove
// VECTYPE
// fields of this structure type should include:
// next, coeff
// GEOHEAP_SIZE: defined in style.hpp
// heap_size: defined in object.cpp
template <class FREEMODULETYPE, class VECTYPE>
class geobucket
{
FREEMODULETYPE *F; // Our elements will be vectors in here
const Ring *K; // The coefficient ring
VECTYPE heap[GEOHEAP_SIZE];
int top_of_heap;
int mLead; // set after a call to get_lead_term.
// set negative after each call to add,
// or remove_lead_term
public:
geobucket(FREEMODULETYPE *F);
~geobucket();
void add(VECTYPE p);
const VECTYPE get_lead_term(); // Returns NULL if none.
VECTYPE remove_lead_term(); // Returns NULL if none.
FREEMODULETYPE *get_target() const { return F; }
VECTYPE value(); // Returns the linearized value, and resets the geobucket.
VECTYPE debug_list(int i) { return heap[i]; } // DO NOT USE, except for debugging purposes!
VECTYPE current_value() const; // Adds up all the elements and returns this value
// Mainly used for debugging.
};
template <class FREEMODULETYPE, class VECTYPE>
inline geobucket<FREEMODULETYPE, VECTYPE>::geobucket(FREEMODULETYPE *FF)
: F(FF),
K(FF->get_ring()->getCoefficientRing()),
top_of_heap(-1),
mLead(-1)
{
// set K
int i;
for (i=0; i<GEOHEAP_SIZE; i++)
heap[i] = NULL;
}
template <class FREEMODULETYPE, class VECTYPE>
inline geobucket<FREEMODULETYPE, VECTYPE>::~geobucket()
{
// The user of this class must insure that all 'vecterm's
// have been removed first. Thus, we don't need to
// do anything here.
}
template <class FREEMODULETYPE, class VECTYPE>
inline void geobucket<FREEMODULETYPE, VECTYPE>::add(VECTYPE p)
{
mLead = -1;
int len = F->n_terms(p);
int i= 0;
while (len >= heap_size[i]) i++;
F->add_to(heap[i], p);
len = F->n_terms(heap[i]);
p = NULL;
while (len >= heap_size[i])
{
i++;
F->add_to(heap[i], heap[i-1]);
len = F->n_terms(heap[i]);
heap[i-1] = NULL;
}
if (i > top_of_heap)
top_of_heap = i;
}
template <class FREEMODULETYPE, class VECTYPE>
inline const VECTYPE geobucket<FREEMODULETYPE, VECTYPE>::get_lead_term()
{
int lead_so_far = -1;
for (int i=0; i <= top_of_heap; i++)
{
if (heap[i] == NULL) continue;
if (lead_so_far < 0)
{
lead_so_far = i;
continue;
}
int cmp = F->compare(heap[lead_so_far], heap[i]);
if (cmp == GT) continue;
if (cmp == LT)
{
lead_so_far = i;
continue;
}
// At this point we have equality
K->add_to(heap[lead_so_far]->coeff, heap[i]->coeff);
VECTYPE tmp = heap[i];
heap[i] = tmp->next;
tmp->next = NULL;
F->remove(tmp);
if (K->is_zero(heap[lead_so_far]->coeff))
{
// Remove, and start over
tmp = heap[lead_so_far];
heap[lead_so_far] = tmp->next;
tmp->next = NULL;
F->remove(tmp);
lead_so_far = -1;
i = -1;
}
}
mLead = lead_so_far;
if (lead_so_far < 0) return NULL;
VECTYPE result = heap[lead_so_far];
return result;
}
template <class FREEMODULETYPE, class VECTYPE>
inline VECTYPE geobucket<FREEMODULETYPE, VECTYPE>::remove_lead_term()
{
if (mLead < 0) get_lead_term();
if (mLead < 0) return NULL;
VECTYPE result = heap[mLead];
heap[mLead] = result->next;
result->next = NULL;
mLead = -1;
return result;
}
template <class FREEMODULETYPE, class VECTYPE>
inline VECTYPE geobucket<FREEMODULETYPE, VECTYPE>::value()
{
VECTYPE result = NULL;
for (int i=0; i<=top_of_heap; i++)
{
if (heap[i] == NULL) continue;
F->add_to(result, heap[i]);
heap[i] = NULL;
}
top_of_heap = -1;
return result;
}
template <class FREEMODULETYPE, class VECTYPE>
inline VECTYPE geobucket<FREEMODULETYPE, VECTYPE>::current_value() const
{
VECTYPE result = NULL;
for (int i=0; i<=top_of_heap; i++)
{
if (heap[i] == NULL) continue;
VECTYPE tmp = F->copy(heap[i]);
F->add_to(result, tmp);
}
return result;
}
// Local Variables:
// compile-command: "make -C $M2BUILDDIR/Macaulay2/e "
// End:
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