add base_margin

src/gbm/gbtree-inl.hpp

@@ -233,7 +233,7 @@ class GBTree : public IGradBooster<FMatrix> {
       pred_counter[bid] = static_cast<unsigned>(trees.size());
       pred_buffer[bid] = psum;
     }
-    return psum + mparam.base_score;
+    return psum;
   }
   // initialize thread local space for prediction
   inline void InitThreadTemp(int nthread) {
@@ -296,8 +296,6 @@ class GBTree : public IGradBooster<FMatrix> {
   };
   /*! \brief model parameters */
   struct ModelParam {
-    /*! \brief base prediction score of everything */
-    float base_score;
     /*! \brief number of trees */
     int num_trees;
     /*! \brief number of root: default 0, means single tree */
@@ -316,7 +314,6 @@ class GBTree : public IGradBooster<FMatrix> {
     int reserved[32];
     /*! \brief constructor */
     ModelParam(void) {
-      base_score = 0.0f;
       num_trees = 0;
       num_roots = num_feature = 0;
       num_pbuffer = 0;
@@ -329,7 +326,6 @@ class GBTree : public IGradBooster<FMatrix> {
      * \param val  value of the parameter
      */
     inline void SetParam(const char *name, const char *val) {
-      if (!strcmp("base_score", name)) base_score = static_cast<float>(atof(val));
       if (!strcmp("num_pbuffer", name)) num_pbuffer = atol(val);
       if (!strcmp("num_output_group", name)) num_output_group = atol(val);
       if (!strcmp("bst:num_roots", name)) num_roots = atoi(val);