1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
|
#include "viterbi_envelope.h"
#include <cassert>
#include <limits>
using namespace std;
using boost::shared_ptr;
ostream& operator<<(ostream& os, const ViterbiEnvelope& env) {
os << '<';
const vector<shared_ptr<Segment> >& segs = env.GetSortedSegs();
for (int i = 0; i < segs.size(); ++i)
os << (i==0 ? "" : "|") << "x=" << segs[i]->x << ",b=" << segs[i]->b << ",m=" << segs[i]->m << ",p1=" << segs[i]->p1 << ",p2=" << segs[i]->p2;
return os << '>';
}
ViterbiEnvelope::ViterbiEnvelope(int i) {
if (i == 0) {
// do nothing - <>
} else if (i == 1) {
segs.push_back(shared_ptr<Segment>(new Segment(0, 0, 0, shared_ptr<Segment>(), shared_ptr<Segment>())));
assert(this->IsMultiplicativeIdentity());
} else {
cerr << "Only can create ViterbiEnvelope semiring 0 and 1 with this constructor!\n";
abort();
}
}
struct SlopeCompare {
bool operator() (const shared_ptr<Segment>& a, const shared_ptr<Segment>& b) const {
return a->m < b->m;
}
};
const ViterbiEnvelope& ViterbiEnvelope::operator+=(const ViterbiEnvelope& other) {
if (!other.is_sorted) other.Sort();
if (segs.empty()) {
segs = other.segs;
return *this;
}
is_sorted = false;
int j = segs.size();
segs.resize(segs.size() + other.segs.size());
for (int i = 0; i < other.segs.size(); ++i)
segs[j++] = other.segs[i];
assert(j == segs.size());
return *this;
}
void ViterbiEnvelope::Sort() const {
sort(segs.begin(), segs.end(), SlopeCompare());
const int k = segs.size();
int j = 0;
for (int i = 0; i < k; ++i) {
Segment l = *segs[i];
l.x = kMinusInfinity;
// cerr << "m=" << l.m << endl;
if (0 < j) {
if (segs[j-1]->m == l.m) { // lines are parallel
if (l.b <= segs[j-1]->b) continue;
--j;
}
while(0 < j) {
l.x = (l.b - segs[j-1]->b) / (segs[j-1]->m - l.m);
if (segs[j-1]->x < l.x) break;
--j;
}
if (0 == j) l.x = kMinusInfinity;
}
*segs[j++] = l;
}
segs.resize(j);
is_sorted = true;
}
const ViterbiEnvelope& ViterbiEnvelope::operator*=(const ViterbiEnvelope& 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;
shared_ptr<Segment> edge_parent = segs[0];
const double& edge_b = edge_parent->b;
const double& edge_m = edge_parent->m;
segs.clear();
for (int i = 0; i < other.segs.size(); ++i) {
const Segment& seg = *other.segs[i];
const double m = seg.m + edge_m;
const double b = seg.b + edge_b;
const double& x = seg.x; // x's don't change with *
segs.push_back(shared_ptr<Segment>(new Segment(x, m, b, edge_parent, other.segs[i])));
assert(segs.back()->p1->rule);
}
// if (other.size() > 1)
// cerr << " = " << *this << endl;
} else {
vector<shared_ptr<Segment> > new_segs;
int this_i = 0;
int other_i = 0;
const int this_size = segs.size();
const int other_size = other.segs.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 ? segs[1]->x : kPlusInfinity);
double other_next_val = (1 < other_size ? other.segs[1]->x : kPlusInfinity);
while (this_i < this_size && other_i < other_size) {
const Segment& this_seg = *segs[this_i];
const Segment& other_seg= *other.segs[other_i];
const double m = this_seg.m + other_seg.m;
const double b = this_seg.b + other_seg.b;
new_segs.push_back(shared_ptr<Segment>(new Segment(cur_x, m, b, segs[this_i], other.segs[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 ? segs[this_i+1]->x : kPlusInfinity);
other_next_val = (other_i+1 < other_size ? other.segs[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 ? segs[this_i+1]->x : kPlusInfinity);
} else {
++other_i;
cur_x = other_next_val;
other_next_val = (other_i+1 < other_size ? other.segs[other_i+1]->x : kPlusInfinity);
}
}
}
segs.swap(new_segs);
}
//cerr << "Multiply: result=" << (*this) << endl;
return *this;
}
// recursively construct translation
void Segment::ConstructTranslation(vector<WordID>* trans) const {
const Segment* cur = this;
vector<vector<WordID> > ant_trans;
while(!cur->rule) {
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);
--ant_size;
for (int i = 0; i < pants.size(); ++i) pants[ant_size - i] = &ant_trans[i];
cur->rule->ESubstitute(pants, trans);
}
ViterbiEnvelope ViterbiEnvelopeWeightFunction::operator()(const Hypergraph::Edge& e) const {
const double m = direction.dot(e.feature_values_);
const double b = origin.dot(e.feature_values_);
Segment* seg = new Segment(m, b, e.rule_);
return ViterbiEnvelope(1, seg);
}
|
