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-rw-r--r--decoder/lattice.cc62
1 files changed, 62 insertions, 0 deletions
diff --git a/decoder/lattice.cc b/decoder/lattice.cc
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--- /dev/null
+++ b/decoder/lattice.cc
@@ -0,0 +1,62 @@
+#include "lattice.h"
+
+#include "tdict.h"
+#include "hg_io.h"
+
+using namespace std;
+
+static const int kUNREACHABLE = 99999999;
+
+void Lattice::ComputeDistances() {
+ const int n = this->size() + 1;
+ dist_.resize(n, n, kUNREACHABLE);
+ for (int i = 0; i < this->size(); ++i) {
+ const vector<LatticeArc>& alts = (*this)[i];
+ for (int j = 0; j < alts.size(); ++j)
+ dist_(i, i + alts[j].dist2next) = 1;
+ }
+ for (int k = 0; k < n; ++k) {
+ for (int i = 0; i < n; ++i) {
+ for (int j = 0; j < n; ++j) {
+ const int dp = dist_(i,k) + dist_(k,j);
+ if (dist_(i,j) > dp)
+ dist_(i,j) = dp;
+ }
+ }
+ }
+
+ for (int i = 0; i < n; ++i) {
+ int latest = kUNREACHABLE;
+ for (int j = n-1; j >= 0; --j) {
+ const int c = dist_(i,j);
+ if (c < kUNREACHABLE)
+ latest = c;
+ else
+ dist_(i,j) = latest;
+ }
+ }
+ // cerr << dist_ << endl;
+}
+
+bool LatticeTools::LooksLikePLF(const string &line) {
+ return (line.size() > 5) && (line.substr(0,4) == "((('");
+}
+
+void LatticeTools::ConvertTextToLattice(const string& text, Lattice* pl) {
+ Lattice& l = *pl;
+ vector<WordID> ids;
+ TD::ConvertSentence(text, &ids);
+ l.resize(ids.size());
+ for (int i = 0; i < l.size(); ++i)
+ l[i].push_back(LatticeArc(ids[i], 0.0, 1));
+ l.is_sentence_ = true;
+}
+
+void LatticeTools::ConvertTextOrPLF(const string& text_or_plf, Lattice* pl) {
+ if (LooksLikePLF(text_or_plf))
+ HypergraphIO::PLFtoLattice(text_or_plf, pl);
+ else
+ ConvertTextToLattice(text_or_plf, pl);
+ pl->ComputeDistances();
+}
+