initial check in

1 files changed, 167 insertions, 0 deletions

diff --git a/vest/viterbi_envelope.cc b/vest/viterbi_envelope.cc
new file mode 100644
index 00000000..1122030a
--- /dev/null
+++ b/vest/viterbi_envelope.cc
@@ -0,0 +1,167 @@
+#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);
+}
+