From 1b8181bf0d6e9137e6b9ccdbe414aec37377a1a9 Mon Sep 17 00:00:00 2001
From: Chris Dyer <cdyer@allegro.clab.cs.cmu.edu>
Date: Sun, 18 Nov 2012 13:35:42 -0500
Subject: major restructure of the training code

---
 training/dtrain/ksampler.h | 61 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 61 insertions(+)
 create mode 100644 training/dtrain/ksampler.h

(limited to 'training/dtrain/ksampler.h')

diff --git a/training/dtrain/ksampler.h b/training/dtrain/ksampler.h
new file mode 100644
index 00000000..bc2f56cd
--- /dev/null
+++ b/training/dtrain/ksampler.h
@@ -0,0 +1,61 @@
+#ifndef _DTRAIN_KSAMPLER_H_
+#define _DTRAIN_KSAMPLER_H_
+
+#include "hg_sampler.h" // cdec
+#include "kbestget.h"
+#include "score.h"
+
+namespace dtrain
+{
+
+bool
+cmp_hyp_by_model_d(ScoredHyp a, ScoredHyp b)
+{
+  return a.model > b.model;
+}
+
+struct KSampler : public HypSampler
+{
+  const unsigned k_;
+  vector<ScoredHyp> s_;
+  MT19937* prng_;
+  score_t (*scorer)(NgramCounts&, const unsigned, const unsigned, unsigned, vector<score_t>);
+  unsigned src_len_;
+
+  explicit KSampler(const unsigned k, MT19937* prng) :
+    k_(k), prng_(prng) {}
+
+  virtual void
+  NotifyTranslationForest(const SentenceMetadata& smeta, Hypergraph* hg)
+  {
+    src_len_ = smeta.GetSourceLength();
+    ScoredSamples(*hg);
+  }
+
+  vector<ScoredHyp>* GetSamples() { return &s_; }
+
+  void ScoredSamples(const Hypergraph& forest) {
+    s_.clear(); sz_ = f_count_ = 0;
+    std::vector<HypergraphSampler::Hypothesis> samples;
+    HypergraphSampler::sample_hypotheses(forest, k_, prng_, &samples);
+    for (unsigned i = 0; i < k_; ++i) {
+      ScoredHyp h;
+      h.w = samples[i].words;
+      h.f = samples[i].fmap;
+      h.model = log(samples[i].model_score);
+      h.rank = i;
+      h.score = scorer_->Score(h.w, *ref_, i, src_len_);
+      s_.push_back(h);
+      sz_++;
+      f_count_ += h.f.size();
+    }
+    sort(s_.begin(), s_.end(), cmp_hyp_by_model_d);
+    for (unsigned i = 0; i < s_.size(); i++) s_[i].rank = i;
+  }
+};
+
+
+} // namespace
+
+#endif
+
-- 
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