check pipe, commit optimization for hist

multi-node/row-split/README.md

@@ -15,4 +15,4 @@ Notes
 * The code is multi-threaded, so you want to run one xgboost-mpi per node
 * Row-based solver split data by row, each node work on subset of rows, it uses an approximate histogram count algorithm,
   and will only examine subset of potential split points as opposed to all split points.
-* ```colsample_bytree``` is not enabled in row split mode so far
+

multi-node/row-split/machine-row.conf

@@ -14,7 +14,6 @@ gamma = 1.0
 min_child_weight = 1 
 # maximum depth of a tree
 max_depth = 3 
-
 # Task parameters
 # the number of round to do boosting
 num_round = 2

multi-node/row-split/mushroom-row.sh

@@ -12,7 +12,7 @@ k=$1
 python splitrows.py ../../demo/data/agaricus.txt.train train $k
 
 # run xgboost mpi
-mpirun -n $k ../../xgboost-mpi mushroom-row.conf dsplit=row nthread=1
+mpirun -n $k ../../xgboost-mpi mushroom-row.conf dsplit=row nthread=1 
 
 # the model can be directly loaded by single machine xgboost solver, as usuall
 ../../xgboost mushroom-row.conf task=dump model_in=0002.model fmap=../../demo/data/featmap.txt name_dump=dump.nice.$k.txt