File size: 5,764 Bytes
158b61b |
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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 |
#include "PatternApplicationTrie.h"
#include "moses/Syntax/PVertex.h"
namespace Moses
{
namespace Syntax
{
namespace S2T
{
int PatternApplicationTrie::Depth() const
{
if (m_parent) {
return m_parent->Depth() + 1;
}
return 0;
}
const PatternApplicationTrie *
PatternApplicationTrie::GetHighestTerminalNode() const
{
// Check if result has been cached.
if (m_highestTerminalNode) {
return m_highestTerminalNode;
}
// It doesn't really make sense to call this on the root node. Just return 0.
if (!m_parent) {
return 0;
}
// Is this the highest non-root node?
if (!m_parent->m_parent) {
if (IsTerminalNode()) {
m_highestTerminalNode = this;
return this;
} else {
return 0;
}
}
// This is not the highest non-root node, so ask parent node.
if (const PatternApplicationTrie *p = m_parent->GetHighestTerminalNode()) {
m_highestTerminalNode = p;
return p;
}
// There are no terminal nodes higher than this node.
if (IsTerminalNode()) {
m_highestTerminalNode = this;
}
return m_highestTerminalNode;
}
const PatternApplicationTrie *
PatternApplicationTrie::GetLowestTerminalNode() const
{
// Check if result has been cached.
if (m_lowestTerminalNode) {
return m_lowestTerminalNode;
}
// It doesn't really make sense to call this on the root node. Just return 0.
if (!m_parent) {
return 0;
}
// Is this a terminal node?
if (IsTerminalNode()) {
m_lowestTerminalNode = this;
return this;
}
// Is this the highest non-root node?
if (!m_parent->m_parent) {
return 0;
}
// Ask parent node.
return m_parent->GetLowestTerminalNode();
}
// A node corresponds to a rule pattern that has been partially applied to a
// sentence (the terminals have fixed positions, but the spans of gap symbols
// may be unknown). This function determines the range of possible start
// values for the partially-applied pattern.
void PatternApplicationTrie::DetermineStartRange(int sentenceLength,
int &minStart,
int &maxStart) const
{
// Find the leftmost terminal symbol, if any.
const PatternApplicationTrie *n = GetHighestTerminalNode();
if (!n) {
// The pattern contains only gap symbols.
minStart = 0;
maxStart = sentenceLength-Depth();
return;
}
assert(n->m_parent);
if (!n->m_parent->m_parent) {
// The pattern begins with a terminal symbol so the start position is
// fixed.
minStart = n->m_start;
maxStart = n->m_start;
} else {
// The pattern begins with a gap symbol but it contains at least one
// terminal symbol. The maximum start position is the start position of
// the leftmost terminal minus one position for each leading gap symbol.
minStart = 0;
maxStart = n->m_start - (n->Depth()-1);
}
}
// A node corresponds to a rule pattern that has been partially applied to a
// sentence (the terminals have fixed positions, but the spans of gap symbols
// may be unknown). This function determines the range of possible end values
// for the partially-applied pattern.
void PatternApplicationTrie::DetermineEndRange(int sentenceLength,
int &minEnd,
int &maxEnd) const
{
// Find the rightmost terminal symbol, if any.
const PatternApplicationTrie *n = GetLowestTerminalNode();
if (!n) {
// The pattern contains only gap symbols.
minEnd = Depth()-1;
maxEnd = sentenceLength-1;
return;
}
if (n == this) {
// The pattern ends with a terminal symbol so the end position is fixed.
minEnd = m_end;
maxEnd = m_end;
} else {
// The pattern ends with a gap symbol but it contains at least one terminal
// symbol. The minimum end position is the end position of the rightmost
// terminal + one position for each trailing gap symbol.
minEnd = n->m_end + (Depth()-n->Depth());
maxEnd = sentenceLength-1;
}
}
void PatternApplicationTrie::Extend(const RuleTrieScope3::Node &node,
int minPos, const SentenceMap &sentMap,
bool followsGap)
{
const RuleTrieScope3::Node::TerminalMap &termMap = node.GetTerminalMap();
for (RuleTrieScope3::Node::TerminalMap::const_iterator p = termMap.begin();
p != termMap.end(); ++p) {
const Word &word = p->first;
const RuleTrieScope3::Node &child = p->second;
SentenceMap::const_iterator q = sentMap.find(word);
if (q == sentMap.end()) {
continue;
}
for (std::vector<const PVertex *>::const_iterator r = q->second.begin();
r != q->second.end(); ++r) {
const PVertex *v = *r;
std::size_t start = v->span.GetStartPos();
std::size_t end = v->span.GetEndPos();
if (start == (std::size_t)minPos ||
(followsGap && start > (std::size_t)minPos) ||
minPos == -1) {
PatternApplicationTrie *subTrie =
new PatternApplicationTrie(start, end, child, v, this);
subTrie->Extend(child, end+1, sentMap, false);
m_children.push_back(subTrie);
}
}
}
const RuleTrieScope3::Node *child = node.GetNonTerminalChild();
if (!child) {
return;
}
int start = followsGap ? -1 : minPos;
PatternApplicationTrie *subTrie =
new PatternApplicationTrie(start, -1, *child, 0, this);
int newMinPos = (minPos == -1 ? 1 : minPos+1);
subTrie->Extend(*child, newMinPos, sentMap, true);
m_children.push_back(subTrie);
}
void PatternApplicationTrie::ReadOffPatternApplicationKey(
PatternApplicationKey &key) const
{
const int depth = Depth();
key.resize(depth);
const PatternApplicationTrie *p = this;
std::size_t i = depth-1;
while (p->m_parent != 0) {
key[i--] = p;
p = p->m_parent;
}
}
} // namespace S2T
} // namespace Moses
} // namespace Syntax
|