separate binary classification and regression demo

demo/binary_classification/runexp.sh

@@ -0,0 +1,12 @@
+#!/bin/bash
+# map feature using indicator encoding, also produce featmap.txt
+python mapfeat.py
+# split train and test
+python mknfold.py agaricus.txt 1
+# training
+../../xgboost mushroom.conf
+# this is what dump will looklike without feature map
+../../xgboost mushroom.conf task=dump model_in=0003.model name_dump=dump.raw.txt 
+# this is what dump will looklike with feature map
+../../xgboost mushroom.conf task=dump model_in=0003.model fmap=featmap.txt name_dump=dump.nice.txt
+cat dump.nice.txt