From 5e8e9a9b743e837ccb1e6bf491d153aef6977d9c Mon Sep 17 00:00:00 2001
From: tqchen <tianqi.tchen@gmail.com>
Date: Mon, 17 Nov 2014 10:49:53 -0800
Subject: [PATCH] updated base

---
 src/tree/updater_basemaker-inl.hpp | 110 +++++++++++++++++++++++++----
 1 file changed, 95 insertions(+), 15 deletions(-)

diff --git a/src/tree/updater_basemaker-inl.hpp b/src/tree/updater_basemaker-inl.hpp
index 17469658f..f37335004 100644
--- a/src/tree/updater_basemaker-inl.hpp
+++ b/src/tree/updater_basemaker-inl.hpp
@@ -27,8 +27,8 @@ class BaseMaker: public IUpdater {
  protected:
   // ------static helper functions ------
   // helper function to get to next level of the tree
-  // must work on non-leaf node
-  inline static int NextLevel(const SparseBatch::Inst &inst, const RegTree &tree, int nid) {
+  /*! \brief this is  helper function for row based data*/
+  inline static int NextLevel(const RowBatch::Inst &inst, const RegTree &tree, int nid) {
     const RegTree::Node &n = tree[nid];
     bst_uint findex = n.split_index();
     for (unsigned i = 0; i < inst.length; ++i) {
@@ -52,19 +52,6 @@ class BaseMaker: public IUpdater {
     return nthread;
   }
   // ------class member helpers---------
-  // return decoded position
-  inline int DecodePosition(bst_uint ridx) const{
-    const int pid = position[ridx];
-    return pid < 0 ? ~pid : pid;
-  }
-  // encode the encoded position value for ridx
-  inline void SetEncodePosition(bst_uint ridx, int nid) {
-    if (position[ridx] < 0) {
-      position[ridx] = ~nid;
-    } else {
-      position[ridx] = nid;
-    }
-  }
   /*! \brief initialize temp data structure */
   inline void InitData(const std::vector<bst_gpair> &gpair,
                        const IFMatrix &fmat,
@@ -117,6 +104,99 @@ class BaseMaker: public IUpdater {
     qexpand = newnodes;
     this->UpdateNode2WorkIndex(tree);
   }
+  // return decoded position
+  inline int DecodePosition(bst_uint ridx) const{
+    const int pid = position[ridx];
+    return pid < 0 ? ~pid : pid;
+  }
+  // encode the encoded position value for ridx
+  inline void SetEncodePosition(bst_uint ridx, int nid) {
+    if (position[ridx] < 0) {
+      position[ridx] = ~nid;
+    } else {
+      position[ridx] = nid;
+    }
+  }
+  /*! 
+   * \brief this is helper function uses column based data structure,
+   *        reset the positions to the lastest one
+   * \param nodes the set of nodes that contains the split to be used
+   * \param p_fmat feature matrix needed for tree construction
+   * \param tree the regression tree structure
+   */
+  inline void ResetPositionCol(const std::vector<int> &nodes, IFMatrix *p_fmat, const RegTree &tree) {
+    // set the positions in the nondefault
+    this->SetNonDefaultPositionCol(nodes, p_fmat, tree);
+    // set rest of instances to default position
+    const std::vector<bst_uint> &rowset = p_fmat->buffered_rowset();
+    // set default direct nodes to default
+    // for leaf nodes that are not fresh, mark then to ~nid, 
+    // so that they are ignored in future statistics collection
+    const bst_omp_uint ndata = static_cast<bst_omp_uint>(rowset.size());
+    
+    #pragma omp parallel for schedule(static)
+    for (bst_omp_uint i = 0; i < ndata; ++i) {
+      const bst_uint ridx = rowset[i];
+      const int nid = this->DecodePosition(ridx);
+      if (tree[nid].is_leaf()) {
+        // mark finish when it is not a fresh leaf
+        if (tree[nid].cright() == -1) {
+          position[ridx] = ~nid;
+        }
+        } else {
+        // push to default branch
+        if (tree[nid].default_left()) {
+          this->SetEncodePosition(ridx, tree[nid].cleft());
+        } else {
+          this->SetEncodePosition(ridx, tree[nid].cright());
+        }
+      }
+    }
+  }
+  /*!
+   * \brief this is helper function uses column based data structure,
+   *        update all positions into nondefault branch, if any, ignore the default branch
+   * \param nodes the set of nodes that contains the split to be used
+   * \param p_fmat feature matrix needed for tree construction
+   * \param tree the regression tree structure
+   */
+  virtual void SetNonDefaultPositionCol(const std::vector<int> &nodes,
+                                        IFMatrix *p_fmat, const RegTree &tree) {
+    // step 1, classify the non-default data into right places
+    std::vector<unsigned> fsplits;
+    for (size_t i = 0; i < nodes.size(); ++i) {
+      const int nid = nodes[i];
+      if (!tree[nid].is_leaf()) {
+        fsplits.push_back(tree[nid].split_index());
+      }
+    }
+    std::sort(fsplits.begin(), fsplits.end());
+    fsplits.resize(std::unique(fsplits.begin(), fsplits.end()) - fsplits.begin());
+    
+    utils::IIterator<ColBatch> *iter = p_fmat->ColIterator(fsplits);
+    while (iter->Next()) {
+      const ColBatch &batch = iter->Value();
+      for (size_t i = 0; i < batch.size; ++i) {
+        ColBatch::Inst col = batch[i];
+        const bst_uint fid = batch.col_index[i];
+        const bst_omp_uint ndata = static_cast<bst_omp_uint>(col.length);
+        #pragma omp parallel for schedule(static)
+        for (bst_omp_uint j = 0; j < ndata; ++j) {
+          const bst_uint ridx = col[j].index;
+          const float fvalue = col[j].fvalue;
+          const int nid = this->DecodePosition(ridx);
+          // go back to parent, correct those who are not default
+          if (!tree[nid].is_leaf() && tree[nid].split_index() == fid) {
+            if(fvalue < tree[nid].split_cond()) {
+              this->SetEncodePosition(ridx, tree[nid].cleft());
+            } else {
+              this->SetEncodePosition(ridx, tree[nid].cright());
+            }
+          }
+        }
+      }
+    }
+  }
   /*! \brief training parameter of tree grower */
   TrainParam param;
   /*! \brief queue of nodes to be expanded */