From a0b8bb731c73b2d2ed3e16c0fa79aea93b3be813 Mon Sep 17 00:00:00 2001
From: Chris Dyer <cdyer@cs.cmu.edu>
Date: Tue, 20 Dec 2011 15:51:11 -0500
Subject: new scorer interface is implemented, but not used

---
 mteval/ns_comb.cc | 87 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 87 insertions(+)
 create mode 100644 mteval/ns_comb.cc

(limited to 'mteval/ns_comb.cc')

diff --git a/mteval/ns_comb.cc b/mteval/ns_comb.cc
new file mode 100644
index 00000000..41c634cd
--- /dev/null
+++ b/mteval/ns_comb.cc
@@ -0,0 +1,87 @@
+#include "ns_comb.h"
+
+#include <iostream>
+
+#include "stringlib.h"
+
+using namespace std;
+
+// e.g. COMB:IBM_BLEU=0.5;TER=0.5
+CombinationMetric::CombinationMetric(const std::string& cmd) :
+    EvaluationMetric(cmd),
+    total_size() {
+  if (cmd.find("COMB:") != 0 || cmd.size() < 9) {
+    cerr << "Error in combination metric specifier: " << cmd << endl;
+    exit(1);
+  }
+  string mix = cmd.substr(5);
+  vector<string> comps;
+  Tokenize(cmd.substr(5), ';', &comps);
+  if(comps.size() < 2) {
+    cerr << "Error in combination metric specifier: " << cmd << endl;
+    exit(1);
+  }
+  vector<string> cwpairs;
+  for (unsigned i = 0; i < comps.size(); ++i) {
+    Tokenize(comps[i], '=', &cwpairs);
+    if (cwpairs.size() != 2) { cerr << "Error in combination metric specifier: " << cmd << endl; exit(1); }
+    metrics.push_back(EvaluationMetric::Instance(cwpairs[0]));
+    coeffs.push_back(atof(cwpairs[1].c_str()));
+    offsets.push_back(total_size);
+    total_size += metrics.back()->SufficientStatisticsVectorSize();
+    cerr << (i > 0 ? " + " : "( ") << coeffs.back() << " * " << cwpairs[0];
+  }
+  cerr << " )\n";
+}
+
+struct CombinationSegmentEvaluator : public SegmentEvaluator {
+  CombinationSegmentEvaluator(const string& id,
+                              const vector<vector<WordID> >& refs,
+                              const vector<EvaluationMetric*>& metrics,
+                              const vector<unsigned>& offsets,
+                              const unsigned ts) : id_(id), offsets_(offsets), total_size_(ts), component_evaluators_(metrics.size()) {
+    for (unsigned i = 0; i < metrics.size(); ++i)
+      component_evaluators_[i] = metrics[i]->CreateSegmentEvaluator(refs);
+  }
+  virtual void Evaluate(const std::vector<WordID>& hyp, SufficientStats* out) const {
+    out->id_ = id_;
+    out->fields.resize(total_size_);
+    for (unsigned i = 0; i < component_evaluators_.size(); ++i) {
+      SufficientStats t;
+      component_evaluators_[i]->Evaluate(hyp, &t);
+      for (unsigned j = 0; j < t.fields.size(); ++j) {
+        unsigned op = j + offsets_[i];
+        assert(op < out->fields.size());
+        out->fields[op] = t[j];
+      }
+    }
+  }
+  const string& id_;
+  const vector<unsigned>& offsets_;
+  const unsigned total_size_;
+  vector<boost::shared_ptr<SegmentEvaluator> > component_evaluators_;
+};
+
+boost::shared_ptr<SegmentEvaluator> CombinationMetric::CreateSegmentEvaluator(const std::vector<std::vector<WordID> >& refs) const {
+  boost::shared_ptr<SegmentEvaluator> res;
+  res.reset(new CombinationSegmentEvaluator(MetricId(), refs, metrics, offsets, total_size));
+  return res;
+}
+
+float CombinationMetric::ComputeScore(const SufficientStats& stats) const {
+  float tot = 0;
+  for (unsigned i = 0; i < metrics.size(); ++i) {
+    SufficientStats t;
+    unsigned next = total_size;
+    if (i + 1 < offsets.size()) next = offsets[i+1];
+    for (unsigned j = offsets[i]; j < next; ++j)
+      t.fields.push_back(stats[j]);
+    tot += metrics[i]->ComputeScore(t) * coeffs[i];
+  }
+  return tot;
+}
+
+unsigned CombinationMetric::SufficientStatisticsVectorSize() const {
+  return total_size;
+}
+
-- 
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