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////////////////////////////////////////////////////////////////////////////////
//
// Flip.cc
//
// produced: 18/06/98 jr
//
////////////////////////////////////////////////////////////////////////////////
#include <iostream>
#include <assert.h>
#include <vector>
#include "LabelSet.hh"
#include "Circuits.hh"
#include "Flip.hh"
#include "TriangNode.hh"
namespace topcom {
// class FlipRep:
// constructors:
FlipRep::FlipRep(const Chirotope& chiro, const dependent_set_type& ds, const TriangNode& tn) :
fliprep_type() {
MessageStreams::debug() << "\t\t constructing a flip representation from dependent set " << ds
<< " in " << tn << " in rank " << tn.rank() << " ..." << std::endl;
const Circuit circuit(chiro, ds);
MessageStreams::debug() << "\t\t\t induced circuit is " << circuit << std::endl;
const Simplex c_support(circuit.support());
if (c_support.card() == tn.rank() + 1) {
// general position circuit:
if (tn.containment_ok(circuit)) {
first = circuit.first;
second = circuit.second;
}
else if (tn.containment_ok(circuit.inverse())) {
first = circuit.second;
second = circuit.first;
}
}
else {
// special position circuit:
if (tn.link_ok(circuit)) {
first = circuit.first;
second = circuit.second;
}
else if (tn.link_ok(circuit.inverse())) {
first = circuit.second;
second = circuit.first;
}
}
MessageStreams::debug() << "\t\t induced flip representation is " << *this << "." << std::endl;
}
// class Flip:
// internal algorithms:
void Flip::_construct(const TriangNode& tn, const Circuit& circuit) {
Simplex simp(circuit.support());
// general position circuit:
if (simp.card() == tn.rank() + 1) {
for (LabelSet::const_iterator iter = circuit.first.begin();
iter != circuit.first.end();
++iter) {
simp -= *iter;
first += simp;
simp += *iter;
}
for (LabelSet::const_iterator iter = circuit.second.begin();
iter != circuit.second.end();
++iter) {
simp -= *iter;
second += simp;
simp += *iter;
}
}
else {
// special position circuit:
std::vector<Simplex> common_link;
LabelSet::const_iterator first_iter = circuit.first.begin();
simp -= *first_iter;
for (SimplicialComplex::const_iterator tn_iter = tn.begin();
tn_iter != tn.end();
++tn_iter) {
if (tn_iter->superset(simp)) {
first += *tn_iter;
common_link.push_back(*tn_iter - simp);
}
}
simp += *first_iter;
while (++first_iter != circuit.first.end()) {
simp -= *first_iter;
for (size_type i = 0; i < common_link.size(); ++i) {
first += (simp + common_link[i]);
}
simp += *first_iter;
}
for (LabelSet::const_iterator second_iter = circuit.second.begin();
second_iter != circuit.second.end();
++second_iter) {
simp -= *second_iter;
for (size_type i = 0; i < common_link.size(); ++i) {
second += (simp + common_link[i]);
}
simp += *second_iter;
}
}
}
void Flip::_construct(const Chirotope& chiro, const TriangNode& tn, const dependent_set_type& ds) {
const Circuit circuit(chiro, ds);
_construct(tn, circuit);
}
}; // namespace topcom
// eof Flip.cc
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