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authorWaleed Ammar <wammar@cs.cmu.edu>2012-07-02 16:51:21 -0400
committerWaleed Ammar <wammar@cs.cmu.edu>2012-07-02 16:51:21 -0400
commit5584ad22d3d3fae7ea195fe6cd7cf56cd0f35ba0 (patch)
treed8022f0f613d32551417a520f6c6e29c0c648963 /decoder
parentdc9e428224d95adf63da6460a2031348de295ca1 (diff)
(1) allow prefixes and separators used in feature instantiations to be configured. (2) minor refactoring.
Diffstat (limited to 'decoder')
-rw-r--r--decoder/ff_ngrams.cc85
-rw-r--r--decoder/ff_ngrams.h2
2 files changed, 73 insertions, 14 deletions
diff --git a/decoder/ff_ngrams.cc b/decoder/ff_ngrams.cc
index d6d79f5e..9c13fdbb 100644
--- a/decoder/ff_ngrams.cc
+++ b/decoder/ff_ngrams.cc
@@ -48,6 +48,9 @@ struct State {
namespace {
string Escape(const string& x) {
+ if (x.find('=') == string::npos && x.find(';') == string::npos) {
+ return x;
+ }
string y = x;
for (int i = 0; i < y.size(); ++i) {
if (y[i] == '=') y[i]='_';
@@ -57,10 +60,17 @@ namespace {
}
}
-static bool ParseArgs(string const& in, bool* explicit_markers, unsigned* order) {
+static bool ParseArgs(string const& in, bool* explicit_markers, unsigned* order, vector<string>& prefixes, string& target_separator) {
vector<string> const& argv=SplitOnWhitespace(in);
*explicit_markers = false;
*order = 3;
+ prefixes.push_back("NOT-USED");
+ prefixes.push_back("U:"); // default unigram prefix
+ prefixes.push_back("B:"); // default bigram prefix
+ prefixes.push_back("T:"); // ...etc
+ prefixes.push_back("4:"); // ...etc
+ prefixes.push_back("5:"); // max allowed!
+ target_separator = "_";
#define LMSPEC_NEXTARG if (i==argv.end()) { \
cerr << "Missing argument for "<<*last<<". "; goto usage; \
} else { ++i; }
@@ -73,6 +83,30 @@ static bool ParseArgs(string const& in, bool* explicit_markers, unsigned* order)
case 'x':
*explicit_markers = true;
break;
+ case 'U':
+ LMSPEC_NEXTARG;
+ prefixes[1] = *i;
+ break;
+ case 'B':
+ LMSPEC_NEXTARG;
+ prefixes[2] = *i;
+ break;
+ case 'T':
+ LMSPEC_NEXTARG;
+ prefixes[3] = *i;
+ break;
+ case '4':
+ LMSPEC_NEXTARG;
+ prefixes[4] = *i;
+ break;
+ case '5':
+ LMSPEC_NEXTARG;
+ prefixes[5] = *i;
+ break;
+ case 'S':
+ LMSPEC_NEXTARG;
+ target_separator = *i;
+ break;
case 'o':
LMSPEC_NEXTARG; *order=atoi((*i).c_str());
break;
@@ -86,7 +120,29 @@ static bool ParseArgs(string const& in, bool* explicit_markers, unsigned* order)
}
return true;
usage:
- cerr << "NgramFeatures is incorrect!\n";
+ cerr << "Wrong parameters for NgramFeatures.\n\n"
+
+ << "NgramFeatures Usage: \n"
+ << " feature_function=NgramFeatures filename.lm [-x] [-o <order>] \n"
+ << " [-U <unigram-prefix>] [-B <bigram-prefix>][-T <trigram-prefix>]\n"
+ << " [-4 <4-gram-prefix>] [-5 <5-gram-prefix>] [-S <separator>]\n\n"
+
+ << "Defaults: \n"
+ << " <order> = 3\n"
+ << " <unigram-prefix> = U:\n"
+ << " <bigram-prefix> = B:\n"
+ << " <trigram-prefix> = T:\n"
+ << " <4-gram-prefix> = 4:\n"
+ << " <5-gram-prefix> = 5:\n"
+ << " <separator> = _\n"
+ << " -x (i.e. explicit sos/eos markers) is turned off\n\n"
+
+ << "Example configuration: \n"
+ << " feature_function=NgramFeatures -o 3 -T tri: -S |\n\n"
+
+ << "Example feature instantiation: \n"
+ << " tri:a|b|c \n\n";
+
return false;
}
@@ -158,16 +214,12 @@ class NgramDetectorImpl {
int& fid = ft->fids[curword];
++n;
if (!fid) {
- const char* code="_UBT456789"; // prefix code (unigram, bigram, etc.)
ostringstream os;
- os << code[n] << ':';
+ os << prefixes_[n];
for (int i = n-1; i >= 0; --i) {
- os << (i != n-1 ? "_" : "");
+ os << (i != n-1 ? target_separator_ : "");
const string& tok = TD::Convert(buf[i]);
- if (tok.find('=') == string::npos)
- os << tok;
- else
- os << Escape(tok);
+ os << Escape(tok);
}
fid = FD::Convert(os.str());
}
@@ -297,7 +349,8 @@ class NgramDetectorImpl {
}
public:
- explicit NgramDetectorImpl(bool explicit_markers, unsigned order) :
+ explicit NgramDetectorImpl(bool explicit_markers, unsigned order,
+ vector<string>& prefixes, string& target_separator) :
kCDEC_UNK(TD::Convert("<unk>")) ,
add_sos_eos_(!explicit_markers) {
order_ = order;
@@ -305,6 +358,8 @@ class NgramDetectorImpl {
unscored_size_offset_ = (order_ - 1) * sizeof(WordID);
is_complete_offset_ = unscored_size_offset_ + 1;
unscored_words_offset_ = is_complete_offset_ + 1;
+ prefixes_ = prefixes;
+ target_separator_ = target_separator;
// special handling of beginning / ending sentence markers
dummy_state_ = new char[state_size_];
@@ -340,6 +395,8 @@ class NgramDetectorImpl {
char* dummy_state_;
vector<const void*> dummy_ants_;
TRulePtr dummy_rule_;
+ vector<string> prefixes_;
+ string target_separator_;
struct FidTree {
map<WordID, int> fids;
map<WordID, FidTree> levels;
@@ -348,11 +405,13 @@ class NgramDetectorImpl {
};
NgramDetector::NgramDetector(const string& param) {
- string filename, mapfile, featname;
+ string filename, mapfile, featname, target_separator;
+ vector<string> prefixes;
bool explicit_markers = false;
unsigned order = 3;
- ParseArgs(param, &explicit_markers, &order);
- pimpl_ = new NgramDetectorImpl(explicit_markers, order);
+ ParseArgs(param, &explicit_markers, &order, prefixes, target_separator);
+ pimpl_ = new NgramDetectorImpl(explicit_markers, order, prefixes,
+ target_separator);
SetStateSize(pimpl_->ReserveStateSize());
}
diff --git a/decoder/ff_ngrams.h b/decoder/ff_ngrams.h
index 82f61b33..064dbb49 100644
--- a/decoder/ff_ngrams.h
+++ b/decoder/ff_ngrams.h
@@ -10,7 +10,7 @@
struct NgramDetectorImpl;
class NgramDetector : public FeatureFunction {
public:
- // param = "filename.lm [-o n]"
+ // param = "filename.lm [-o <order>] [-U <unigram-prefix>] [-B <bigram-prefix>] [-T <trigram-prefix>] [-4 <4-gram-prefix>] [-5 <5-gram-prefix>] [-S <separator>]
NgramDetector(const std::string& param);
~NgramDetector();
virtual void FinalTraversalFeatures(const void* context,