new metric

1 files changed, 32 insertions, 0 deletions

diff --git a/mteval/ns_ssk.cc b/mteval/ns_ssk.cc
new file mode 100644
index 00000000..c94e62ca
--- /dev/null
+++ b/mteval/ns_ssk.cc
@@ -0,0 +1,32 @@
+#include "ns_ssk.h"
+
+#include <vector>
+
+#include "kernel_string_subseq.h"
+#include "tdict.h"
+
+static const unsigned kNUMFIELDS = 2;
+static const unsigned kSIMILARITY = 0;
+static const unsigned kCOUNT = 1;
+
+unsigned SSKMetric::SufficientStatisticsVectorSize() const {
+  return kNUMFIELDS;
+}
+
+void SSKMetric::ComputeSufficientStatistics(const std::vector<WordID>& hyp,
+                                            const std::vector<std::vector<WordID> >& refs,
+                                            SufficientStats* out) const {
+  out->fields.resize(kNUMFIELDS);
+  out->fields[kCOUNT] = 1;
+  float bestsim = 0;
+  for (unsigned i = 0; i < refs.size(); ++i) {
+    float s = ssk<4>(hyp, refs[i], 0.8);
+    if (s > bestsim) bestsim = s;
+  }
+  out->fields[kSIMILARITY] = bestsim;
+}
+
+float SSKMetric::ComputeScore(const SufficientStats& stats) const {
+  return stats.fields[kSIMILARITY] / stats.fields[kCOUNT];
+}
+