Instance *SequenceReader::GetNext() {
// Fill all fields for the entire sentence.
vector<vector<string> > sentence_fields;
string line;
if (is_.is_open()) {
while (!is_.eof()) {
getline(is_, line);
if (line.length() <= 0) break;
vector<string> fields;
StringSplit(line, "\t", &fields);
sentence_fields.push_back(fields);
}
}
// Sentence length.
int length = sentence_fields.size();
// Convert to array of words and tags.
vector<string> forms(length);
vector<string> tags(length);
for(int i = 0; i < length; ++i) {
const vector<string> &info = sentence_fields[i];
forms[i] = info[0];
tags[i] = info[1];
}
SequenceInstance *instance = NULL;
if (length > 0) {
instance = new SequenceInstance;
instance->Initialize(forms, tags);
}
return static_cast<Instance*>(instance);
}
void TokenDictionary::InitializeFromSequenceReader(SequenceReader *reader) {
LOG(INFO) << "Creating token dictionary...";
int form_cutoff = FLAGS_form_cutoff;
int form_lower_cutoff = FLAGS_form_cutoff;
int shape_cutoff = 0;
int prefix_length = FLAGS_prefix_length;
int suffix_length = FLAGS_suffix_length;
bool form_case_sensitive = FLAGS_form_case_sensitive;
std::vector<int> form_freqs;
std::vector<int> form_lower_freqs;
std::vector<int> shape_freqs;
Alphabet form_alphabet;
Alphabet form_lower_alphabet;
Alphabet shape_alphabet;
std::string special_symbols[NUM_SPECIAL_TOKENS];
special_symbols[TOKEN_UNKNOWN] = kTokenUnknown;
special_symbols[TOKEN_START] = kTokenStart;
special_symbols[TOKEN_STOP] = kTokenStop;
for (int i = 0; i < NUM_SPECIAL_TOKENS; ++i) {
prefix_alphabet_.Insert(special_symbols[i]);
suffix_alphabet_.Insert(special_symbols[i]);
form_alphabet.Insert(special_symbols[i]);
form_lower_alphabet.Insert(special_symbols[i]);
shape_alphabet.Insert(special_symbols[i]);
// Counts of special symbols are set to -1:
form_freqs.push_back(-1);
form_lower_freqs.push_back(-1);
shape_freqs.push_back(-1);
}
// Go through the corpus and build the dictionaries,
// counting the frequencies.
reader->Open(pipe_->GetOptions()->GetTrainingFilePath());
SequenceInstance *instance =
static_cast<SequenceInstance*>(reader->GetNext());
while (instance != NULL) {
int instance_length = instance->size();
for (int i = 0; i < instance_length; ++i) {
int id;
// Add form to alphabet.
std::string form = instance->GetForm(i);
std::string form_lower(form);
transform(form_lower.begin(), form_lower.end(), form_lower.begin(),
::tolower);
if (!form_case_sensitive) form = form_lower;
id = form_alphabet.Insert(form);
if (id >= form_freqs.size()) {
CHECK_EQ(id, form_freqs.size());
form_freqs.push_back(0);
}
++form_freqs[id];
// Add lower-case form to the alphabet.
id = form_lower_alphabet.Insert(form_lower);
if (id >= form_lower_freqs.size()) {
CHECK_EQ(id, form_lower_freqs.size());
form_lower_freqs.push_back(0);
}
++form_lower_freqs[id];
// Add prefix/suffix to alphabet.
std::string prefix = form.substr(0, prefix_length);
id = prefix_alphabet_.Insert(prefix);
int start = form.length() - suffix_length;
if (start < 0) start = 0;
std::string suffix = form.substr(start, suffix_length);
id = suffix_alphabet_.Insert(suffix);
// Add shape to alphabet.
std::string shape;
GetWordShape(instance->GetForm(i), &shape);
id = shape_alphabet.Insert(shape);
if (id >= shape_freqs.size()) {
CHECK_EQ(id, shape_freqs.size());
shape_freqs.push_back(0);
}
++shape_freqs[id];
}
delete instance;
instance = static_cast<SequenceInstance*>(reader->GetNext());
}
reader->Close();
// Now adjust the cutoffs if necessary.
while (true) {
form_alphabet_.clear();
for (int i = 0; i < NUM_SPECIAL_TOKENS; ++i) {
form_alphabet_.Insert(special_symbols[i]);
}
for (Alphabet::iterator iter = form_alphabet.begin();
iter != form_alphabet.end();
++iter) {
if (form_freqs[iter->second] > form_cutoff) {
form_alphabet_.Insert(iter->first);
}
}
if (form_alphabet_.size() < kMaxFormAlphabetSize) break;
++form_cutoff;
LOG(INFO) << "Incrementing form cutoff to " << form_cutoff << "...";
}
while (true) {
form_lower_alphabet_.clear();
for (int i = 0; i < NUM_SPECIAL_TOKENS; ++i) {
form_lower_alphabet_.Insert(special_symbols[i]);
}
for (Alphabet::iterator iter = form_lower_alphabet.begin();
iter != form_lower_alphabet.end();
++iter) {
if (form_lower_freqs[iter->second] > form_lower_cutoff) {
form_lower_alphabet_.Insert(iter->first);
}
}
if (form_lower_alphabet_.size() < kMaxFormAlphabetSize) break;
++form_lower_cutoff;
LOG(INFO) << "Incrementing lower-case form cutoff to "
<< form_lower_cutoff << "...";
}
while (true) {
shape_alphabet_.clear();
for (int i = 0; i < NUM_SPECIAL_TOKENS; ++i) {
shape_alphabet_.Insert(special_symbols[i]);
}
for (Alphabet::iterator iter = shape_alphabet.begin();
iter != shape_alphabet.end();
++iter) {
if (shape_freqs[iter->second] > shape_cutoff) {
shape_alphabet_.Insert(iter->first);
}
}
if (shape_alphabet_.size() < kMaxShapeAlphabetSize) break;
++shape_cutoff;
LOG(INFO) << "Incrementing shape cutoff to " << shape_cutoff << "...";
}
form_alphabet_.StopGrowth();
form_lower_alphabet_.StopGrowth();
shape_alphabet_.StopGrowth();
lemma_alphabet_.StopGrowth();
prefix_alphabet_.StopGrowth();
suffix_alphabet_.StopGrowth();
feats_alphabet_.StopGrowth();
pos_alphabet_.StopGrowth();
cpos_alphabet_.StopGrowth();
LOG(INFO) << "Number of forms: " << form_alphabet_.size() << endl
<< "Number of prefixes: "
<< prefix_alphabet_.size() << endl
<< "Number of suffixes: "
<< suffix_alphabet_.size() << endl
<< "Number of word shapes: "
<< shape_alphabet_.size();
CHECK_LT(form_alphabet_.size(), 0xffff);
CHECK_LT(form_lower_alphabet_.size(), 0xffff);
CHECK_LT(shape_alphabet_.size(), 0xffff);
CHECK_LT(lemma_alphabet_.size(), 0xffff);
CHECK_LT(prefix_alphabet_.size(), 0xffff);
CHECK_LT(suffix_alphabet_.size(), 0xffff);
CHECK_LT(feats_alphabet_.size(), 0xffff);
CHECK_LT(pos_alphabet_.size(), 0xff);
CHECK_LT(cpos_alphabet_.size(), 0xff);
}
void TaggerDictionary::CreateTagDictionary(SequenceReader *reader) {
SequenceDictionary::CreateTagDictionary(reader);
LOG(INFO) << "Creating word-tag dictionary...";
bool form_case_sensitive = FLAGS_form_case_sensitive;
// Go through the corpus and build the existing tags for each word.
word_tags_.clear();
word_tags_.resize(token_dictionary_->GetNumForms());
reader->Open(pipe_->GetOptions()->GetTrainingFilePath());
SequenceInstance *instance =
static_cast<SequenceInstance*>(reader->GetNext());
while (instance != NULL) {
int instance_length = instance->size();
for (int i = 0; i < instance_length; ++i) {
int id;
string form = instance->GetForm(i);
if (!form_case_sensitive) {
transform(form.begin(), form.end(), form.begin(), ::tolower);
}
int word_id = token_dictionary_->GetFormId(form);
//CHECK_GE(word_id, 0);
id = tag_alphabet_.Lookup(instance->GetTag(i));
CHECK_GE(id, 0);
// Insert new tag in the set of word tags, if it is not there
// already. NOTE: this is inefficient, maybe we should be using a
// different data structure.
if (word_id >= 0) {
vector<int> &tags = word_tags_[word_id];
int j;
for (j = 0; j < tags.size(); ++j) {
if (tags[j] == id) break;
}
if (j == tags.size()) tags.push_back(id);
}
}
delete instance;
instance = static_cast<SequenceInstance*>(reader->GetNext());
}
reader->Close();
// If there is a list of possible tags for the unknown words, load it.
TaggerOptions *options =
static_cast<TaggerOptions*>(pipe_->GetOptions());
if (options->GetUnknownWordTagsFilePath().size() == 0) {
for (int i = 0; i < tag_alphabet_.size(); ++i) {
unknown_word_tags_.push_back(i);
}
} else {
LOG(INFO) << "Loading file with unknown word tags...";
std::ifstream is;
is.open(options->GetUnknownWordTagsFilePath().c_str(), ifstream::in);
CHECK(is.good()) << "Could not open "
<< options->GetUnknownWordTagsFilePath() << ".";
vector<vector<string> > sentence_fields;
string line;
if (is.is_open()) {
while (!is.eof()) {
getline(is, line);
if (line.size() == 0) break;
int tagid = tag_alphabet_.Lookup(line);
CHECK(tagid >= 0) << "Tag " << line << " does not exist.";
unknown_word_tags_.push_back(tagid);
LOG(INFO) << "Unknown word tag: " << line;
}
}
}
LOG(INFO) << "Number of unknown word tags: " << unknown_word_tags_.size();
}
