From 0c3f2babc8c96a3d35b218f3767841f2d5d448d1 Mon Sep 17 00:00:00 2001
From: graehl <graehl@ec762483-ff6d-05da-a07a-a48fb63a330f>
Date: Tue, 6 Jul 2010 22:06:26 +0000
Subject: prune epsilon, comments, use inside pruning for probably no segfaults
 in vest

git-svn-id: https://ws10smt.googlecode.com/svn/trunk@167 ec762483-ff6d-05da-a07a-a48fb63a330f
---
 decoder/hg.cc | 10 +++++-----
 decoder/hg.h  |  1 +
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/decoder/hg.cc b/decoder/hg.cc
index 19dbf892..b6b9d8bd 100644
--- a/decoder/hg.cc
+++ b/decoder/hg.cc
@@ -130,8 +130,8 @@ void Hypergraph::PushWeightsToGoal(double scale) {
 
 struct EdgeExistsWeightFunction {
   EdgeExistsWeightFunction(const std::vector<bool>& prunes) : prunes_(prunes) {}
-  double operator()(const Hypergraph::Edge& edge) const {
-    return (prunes_[edge.id_] ? 0.0 : 1.0);
+  bool operator()(const Hypergraph::Edge& edge) const {
+    return !prunes_[edge.id_];
   }
  private:
   const vector<bool>& prunes_;
@@ -147,8 +147,8 @@ void Hypergraph::PruneEdges(const std::vector<bool>& prune_edge, bool run_inside
     // I don't know a good c++ way to resolve this short of template specialization which
     // I dislike.  If you know of a better way that doesn't involve specialization,
     // fix this!
-    vector<double> reachable;
-    bool goal_derivable = (0 < Inside<double, EdgeExistsWeightFunction>(*this, &reachable, wf));
+    vector<Boolean> reachable;
+    bool goal_derivable = Inside/* <Boolean, EdgeExistsWeightFunction> */(*this, &reachable, wf);
     if (!goal_derivable) {
       edges_.clear();
       nodes_.clear();
@@ -195,7 +195,7 @@ void Hypergraph_finish_prune(Hypergraph &hg,vector<prob_t> const& io,double cuto
   }
   if (verbose)
     cerr << "Finished pruning; removed " << pc << "/" << io.size() << " edges\n";
-  hg.PruneEdges(prune);
+  hg.PruneEdges(prune,true); // inside reachability check in case cutoff rounded down too much (probably redundant with EPSILON hack)
 }
 
 void Hypergraph::DensityPruneInsideOutside(const double scale,
diff --git a/decoder/hg.h b/decoder/hg.h
index a632dc1c..e54b4bcc 100644
--- a/decoder/hg.h
+++ b/decoder/hg.h
@@ -166,6 +166,7 @@ class Hypergraph {
   // remove edges from the hypergraph if prune_edge[edge_id] is true
   // TODO need to investigate why this shouldn't be run for the forest trans
   // case.  To investigate, change false to true and see where ftrans crashes
+  //TODO: what does the above "TODO" comment mean?  that PruneEdges can lead to a crash?  or that run_inside_algorithm should be false?  there definitely is an unsolved bug, see hg.cc - workaround added
   void PruneEdges(const std::vector<bool>& prune_edge, bool run_inside_algorithm = false);
 
   // for density>=1.0, keep this many times the edges needed for the 1best derivation
-- 
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