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authorgraehl <graehl@ec762483-ff6d-05da-a07a-a48fb63a330f>2010-07-06 15:31:18 +0000
committergraehl <graehl@ec762483-ff6d-05da-a07a-a48fb63a330f>2010-07-06 15:31:18 +0000
commit825b1fc172a4f097c94b0fe8137ba2356262b5f4 (patch)
treeb1c1bdd5824eb0edb5be0a306308013a1d67be71 /decoder/hg.cc
parent45b298139d494ee81ce9ea23424faaba5f177230 (diff)
cdec --[prelm_]density_prune
git-svn-id: https://ws10smt.googlecode.com/svn/trunk@150 ec762483-ff6d-05da-a07a-a48fb63a330f
Diffstat (limited to 'decoder/hg.cc')
-rw-r--r--decoder/hg.cc48
1 files changed, 25 insertions, 23 deletions
diff --git a/decoder/hg.cc b/decoder/hg.cc
index 70511c07..11dd6f44 100644
--- a/decoder/hg.cc
+++ b/decoder/hg.cc
@@ -175,10 +175,31 @@ void Hypergraph::PruneEdges(const std::vector<bool>& prune_edge, bool run_inside
TopologicallySortNodesAndEdges(nodes_.size() - 1, &filtered);
}
+void Hypergraph_finish_prune(Hypergraph &hg,vector<prob_t> const& io,double cutoff,vector<bool> const* preserve_mask,bool verbose=false)
+{
+ vector<bool> prune(hg.NumberOfEdges());
+ if (verbose) {
+ if (preserve_mask) cerr << preserve_mask->size() << " " << prune.size() << endl;
+ cerr<<"Finishing prune for "<<prune.size()<<" edges; CUTOFF=" << cutoff << endl;
+ }
+ unsigned pc = 0;
+ for (int i = 0; i < io.size(); ++i) {
+ const bool prune_edge = (io[i] < cutoff);
+ if (prune_edge) {
+ ++pc;
+ prune[i] = !(preserve_mask && (*preserve_mask)[i]);
+ }
+ }
+ if (verbose)
+ cerr << "Finished pruning; removed " << pc << "/" << io.size() << " edges\n";
+ hg.PruneEdges(prune);
+}
+
void Hypergraph::DensityPruneInsideOutside(const double scale,
const bool use_sum_prod_semiring,
const double density,
- const vector<bool>* preserve_mask) {
+ const vector<bool>* preserve_mask)
+{
assert(density >= 1.0);
const int plen = ViterbiPathLength(*this);
vector<WordID> bp;
@@ -195,13 +216,7 @@ void Hypergraph::DensityPruneInsideOutside(const double scale,
assert(edges_.size() == io.size());
vector<prob_t> sorted = io;
nth_element(sorted.begin(), sorted.begin() + rnum, sorted.end(), greater<prob_t>());
- const double cutoff = sorted[rnum];
- vector<bool> prune(edges_.size());
- for (int i = 0; i < edges_.size(); ++i) {
- prune[i] = (io[i] < cutoff);
- if (preserve_mask && (*preserve_mask)[i]) prune[i] = false;
- }
- PruneEdges(prune);
+ Hypergraph_finish_prune(*this,io,sorted[rnum],preserve_mask);
}
void Hypergraph::BeamPruneInsideOutside(
@@ -209,7 +224,7 @@ void Hypergraph::BeamPruneInsideOutside(
const bool use_sum_prod_semiring,
const double alpha,
const vector<bool>* preserve_mask) {
- assert(alpha >= 0.0);
+ assert(alpha > 0.0);
assert(scale > 0.0);
vector<prob_t> io(edges_.size());
if (use_sum_prod_semiring)
@@ -220,20 +235,7 @@ void Hypergraph::BeamPruneInsideOutside(
prob_t best; // initializes to zero
for (int i = 0; i < io.size(); ++i)
if (io[i] > best) best = io[i];
- const prob_t aprob(exp(-alpha));
- const prob_t cutoff = best * aprob;
- // cerr << "aprob = " << aprob << "\t CUTOFF=" << cutoff << endl;
- vector<bool> prune(edges_.size());
- //cerr << preserve_mask.size() << " " << edges_.size() << endl;
- int pc = 0;
- for (int i = 0; i < io.size(); ++i) {
- const bool prune_edge = (io[i] < cutoff);
- if (prune_edge) ++pc;
- prune[i] = (io[i] < cutoff);
- if (preserve_mask && (*preserve_mask)[i]) prune[i] = false;
- }
- // cerr << "Beam pruning " << pc << "/" << io.size() << " edges\n";
- PruneEdges(prune);
+ Hypergraph_finish_prune(*this,io,best*exp(-alpha),preserve_mask);
}
void Hypergraph::PrintGraphviz() const {