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#include "mert_geometry.h"
#include <cassert>
#include <limits>
using namespace std;
ConvexHull::ConvexHull(int i) {
if (i == 0) {
// do nothing - <>
} else if (i == 1) {
points.push_back(boost::shared_ptr<MERTPoint>(new MERTPoint(0, 0, 0, boost::shared_ptr<MERTPoint>(), boost::shared_ptr<MERTPoint>())));
assert(this->IsMultiplicativeIdentity());
} else {
cerr << "Only can create ConvexHull semiring 0 and 1 with this constructor!\n";
abort();
}
}
const ConvexHull ConvexHullWeightFunction::operator()(const Hypergraph::Edge& e) const {
const double m = direction.dot(e.feature_values_);
const double b = origin.dot(e.feature_values_);
MERTPoint* point = new MERTPoint(m, b, e);
return ConvexHull(1, point);
}
ostream& operator<<(ostream& os, const ConvexHull& env) {
os << '<';
const vector<boost::shared_ptr<MERTPoint> >& points = env.GetSortedSegs();
for (int i = 0; i < points.size(); ++i)
os << (i==0 ? "" : "|") << "x=" << points[i]->x << ",b=" << points[i]->b << ",m=" << points[i]->m << ",p1=" << points[i]->p1 << ",p2=" << points[i]->p2;
return os << '>';
}
#define ORIGINAL_MERT_IMPLEMENTATION 1
#ifdef ORIGINAL_MERT_IMPLEMENTATION
struct SlopeCompare {
bool operator() (const boost::shared_ptr<MERTPoint>& a, const boost::shared_ptr<MERTPoint>& b) const {
return a->m < b->m;
}
};
const ConvexHull& ConvexHull::operator+=(const ConvexHull& other) {
if (!other.is_sorted) other.Sort();
if (points.empty()) {
points = other.points;
return *this;
}
is_sorted = false;
int j = points.size();
points.resize(points.size() + other.points.size());
for (int i = 0; i < other.points.size(); ++i)
points[j++] = other.points[i];
assert(j == points.size());
return *this;
}
void ConvexHull::Sort() const {
sort(points.begin(), points.end(), SlopeCompare());
const int k = points.size();
int j = 0;
for (int i = 0; i < k; ++i) {
MERTPoint l = *points[i];
l.x = kMinusInfinity;
// cerr << "m=" << l.m << endl;
if (0 < j) {
if (points[j-1]->m == l.m) { // lines are parallel
if (l.b <= points[j-1]->b) continue;
--j;
}
while(0 < j) {
l.x = (l.b - points[j-1]->b) / (points[j-1]->m - l.m);
if (points[j-1]->x < l.x) break;
--j;
}
if (0 == j) l.x = kMinusInfinity;
}
*points[j++] = l;
}
points.resize(j);
is_sorted = true;
}
const ConvexHull& ConvexHull::operator*=(const ConvexHull& other) {
if (other.IsMultiplicativeIdentity()) { return *this; }
if (this->IsMultiplicativeIdentity()) { (*this) = other; return *this; }
if (!is_sorted) Sort();
if (!other.is_sorted) other.Sort();
if (this->IsEdgeEnvelope()) {
// if (other.size() > 1)
// cerr << *this << " (TIMES) " << other << endl;
boost::shared_ptr<MERTPoint> edge_parent = points[0];
const double& edge_b = edge_parent->b;
const double& edge_m = edge_parent->m;
points.clear();
for (int i = 0; i < other.points.size(); ++i) {
const MERTPoint& p = *other.points[i];
const double m = p.m + edge_m;
const double b = p.b + edge_b;
const double& x = p.x; // x's don't change with *
points.push_back(boost::shared_ptr<MERTPoint>(new MERTPoint(x, m, b, edge_parent, other.points[i])));
assert(points.back()->p1->edge);
}
// if (other.size() > 1)
// cerr << " = " << *this << endl;
} else {
vector<boost::shared_ptr<MERTPoint> > new_points;
int this_i = 0;
int other_i = 0;
const int this_size = points.size();
const int other_size = other.points.size();
double cur_x = kMinusInfinity; // moves from left to right across the
// real numbers, stopping for all inter-
// sections
double this_next_val = (1 < this_size ? points[1]->x : kPlusInfinity);
double other_next_val = (1 < other_size ? other.points[1]->x : kPlusInfinity);
while (this_i < this_size && other_i < other_size) {
const MERTPoint& this_point = *points[this_i];
const MERTPoint& other_point= *other.points[other_i];
const double m = this_point.m + other_point.m;
const double b = this_point.b + other_point.b;
new_points.push_back(boost::shared_ptr<MERTPoint>(new MERTPoint(cur_x, m, b, points[this_i], other.points[other_i])));
int comp = 0;
if (this_next_val < other_next_val) comp = -1; else
if (this_next_val > other_next_val) comp = 1;
if (0 == comp) { // the next values are equal, advance both indices
++this_i;
++other_i;
cur_x = this_next_val; // could be other_next_val (they're equal!)
this_next_val = (this_i+1 < this_size ? points[this_i+1]->x : kPlusInfinity);
other_next_val = (other_i+1 < other_size ? other.points[other_i+1]->x : kPlusInfinity);
} else { // advance the i with the lower x, update cur_x
if (-1 == comp) {
++this_i;
cur_x = this_next_val;
this_next_val = (this_i+1 < this_size ? points[this_i+1]->x : kPlusInfinity);
} else {
++other_i;
cur_x = other_next_val;
other_next_val = (other_i+1 < other_size ? other.points[other_i+1]->x : kPlusInfinity);
}
}
}
points.swap(new_points);
}
//cerr << "Multiply: result=" << (*this) << endl;
return *this;
}
// recursively construct translation
void MERTPoint::ConstructTranslation(vector<WordID>* trans) const {
const MERTPoint* cur = this;
vector<vector<WordID> > ant_trans;
while(!cur->edge) {
ant_trans.resize(ant_trans.size() + 1);
cur->p2->ConstructTranslation(&ant_trans.back());
cur = cur->p1.get();
}
size_t ant_size = ant_trans.size();
vector<const vector<WordID>*> pants(ant_size);
assert(ant_size == cur->edge->tail_nodes_.size());
--ant_size;
for (int i = 0; i < pants.size(); ++i) pants[ant_size - i] = &ant_trans[i];
cur->edge->rule_->ESubstitute(pants, trans);
}
void MERTPoint::CollectEdgesUsed(std::vector<bool>* edges_used) const {
if (edge) {
assert(edge->id_ < edges_used->size());
(*edges_used)[edge->id_] = true;
}
if (p1) p1->CollectEdgesUsed(edges_used);
if (p2) p2->CollectEdgesUsed(edges_used);
}
#else
// THIS IS THE NEW FASTER IMPLEMENTATION OF THE MERT SEMIRING OPERATIONS
#endif
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