diff --git a/src/learner/evaluation-inl.hpp b/src/learner/evaluation-inl.hpp
index bff37ff94..69f0bb4d9 100644
--- a/src/learner/evaluation-inl.hpp
+++ b/src/learner/evaluation-inl.hpp
@@ -159,7 +159,12 @@ struct EvalAMS : public IEvaluator {
 struct EvalPrecisionRatio : public IEvaluator{
  public:
   explicit EvalPrecisionRatio(const char *name) : name_(name) {
-    utils::Assert(sscanf(name, "pratio@%f", &ratio_) == 1, "BUG");
+    if (sscanf(name, "apratio@%f", &ratio_) == 1) {
+      use_ap = 1;
+    } else {
+      utils::Assert(sscanf(name, "pratio@%f", &ratio_) == 1, "BUG");
+      use_ap = 0;
+    }
   }
   virtual float Eval(const std::vector<float> &preds,
                      const MetaInfo &info) const {
@@ -179,13 +184,20 @@ struct EvalPrecisionRatio : public IEvaluator{
  protected:
   inline double CalcPRatio(const std::vector< std::pair<float, unsigned> >& rec, const MetaInfo &info) const {
     size_t cutoff = static_cast<size_t>(ratio_ * rec.size());
-    double wt_hit = 0.0, wsum = 0.0;
+    double wt_hit = 0.0, wsum = 0.0, wt_sum = 0.0;
     for (size_t j = 0; j < cutoff; ++j) {
-      wt_hit += info.labels[rec[j].second];
-      wsum += wt_hit / (j + 1);
-     }
-    return wsum / cutoff;
+      const float wt = info.GetWeight(j);
+      wt_hit += info.labels[rec[j].second] * wt;
+      wt_sum += wt;
+      wsum += wt_hit / wt_sum;
+    }
+    if (use_ap != 0) {
+      return wsum / cutoff;
+    } else {
+      return wt_hit / wt_sum;
+    }
   }
+  int use_ap;
   float ratio_;
   std::string name_;
 };
diff --git a/src/learner/evaluation.h b/src/learner/evaluation.h
index 79ad4902e..02fb8fdf8 100644
--- a/src/learner/evaluation.h
+++ b/src/learner/evaluation.h
@@ -8,6 +8,7 @@
 #include <string>
 #include <vector>
 #include "../utils/utils.h"
+#include "./dmatrix.h"
 
 namespace xgboost {
 namespace learner {
@@ -41,7 +42,8 @@ inline IEvaluator* CreateEvaluator(const char *name) {
   if (!strcmp(name, "auc")) return new EvalAuc();
   if (!strncmp(name, "ams@", 4)) return new EvalAMS(name);
   if (!strncmp(name, "pre@", 4)) return new EvalPrecision(name);
-  if (!strncmp(name, "pratio@", 4)) return new EvalPrecisionRatio(name);
+  if (!strncmp(name, "pratio@", 7)) return new EvalPrecisionRatio(name);
+  if (!strncmp(name, "apratio@", 8)) return new EvalPrecisionRatio(name);
   if (!strncmp(name, "map", 3)) return new EvalMAP(name);
   if (!strncmp(name, "ndcg", 3)) return new EvalNDCG(name);
   utils::Error("unknown evaluation metric type: %s", name);
diff --git a/src/learner/learner-inl.hpp b/src/learner/learner-inl.hpp
index 18611bea5..6d00c3090 100644
--- a/src/learner/learner-inl.hpp
+++ b/src/learner/learner-inl.hpp
@@ -84,6 +84,9 @@ class BoostLearner {
     if (!strcmp(name, "eval_metric")) evaluator_.AddEval(val);
     if (!strcmp("seed", name)) random::Seed(atoi(val));
     if (!strcmp(name, "num_class")) this->SetParam("num_output_group", val);
+    if (!strcmp(name, "nthread")) {
+      omp_set_num_threads(atoi(val));
+    }
     if (gbm_ == NULL) {
       if (!strcmp(name, "objective")) name_obj_ = val;
       if (!strcmp(name, "booster")) name_gbm_ = val;