[python] Evaluation metrics in Python

1 files changed, 44 insertions, 0 deletions

diff --git a/python/src/py_scorer.h b/python/src/py_scorer.h
new file mode 100644
index 00000000..22dc9fee
--- /dev/null
+++ b/python/src/py_scorer.h
@@ -0,0 +1,44 @@
+#include "ns.h"
+#include "tdict.h"
+
+typedef float (*MetricScoreCallback)(void*, SufficientStats* stats);
+typedef void (*MetricStatsCallback)(void*,
+        std::string *hyp,
+        std::vector<std::string> *refs,
+        SufficientStats* out);
+
+struct PythonEvaluationMetric : public EvaluationMetric {
+
+    PythonEvaluationMetric(const std::string& id) : EvaluationMetric(id) {}
+
+    static EvaluationMetric* Instance(const std::string& id, 
+            void* obj,
+            MetricStatsCallback statscb,
+            MetricScoreCallback scorecb) {
+        PythonEvaluationMetric* metric = new PythonEvaluationMetric(id);
+        metric->pymetric = obj;
+        metric->_compute_score =  scorecb;
+        metric->_compute_sufficient_stats = statscb;
+        return metric;
+    }
+
+    float ComputeScore(const SufficientStats& stats) const {
+        SufficientStats stats_(stats);
+        return _compute_score(pymetric, &stats_);
+    }
+
+    void ComputeSufficientStatistics(const std::vector<WordID>& hyp,
+            const std::vector<std::vector<WordID> >& refs,
+            SufficientStats* out) const {
+        std::string hyp_(TD::GetString(hyp));
+        std::vector<std::string> refs_;
+        for(unsigned i = 0; i < refs.size(); ++i) {
+            refs_.push_back(TD::GetString(refs[i]));
+        }
+        _compute_sufficient_stats(pymetric, &hyp_, &refs_, out);
+    }
+
+    void* pymetric;
+    MetricStatsCallback _compute_sufficient_stats;
+    MetricScoreCallback _compute_score;
+};