file my_tree_example.csv :
2.33
2.33
2.33
2.33
2.33
3.33
3.33
3.33
3.33
3.33
2.33
2.33
2.33
2.33
2.33
3.33
3.33
3.33
3.33
3.33
3.33
2.33


file my_tree_labels.csv :
0
0
0
0
0
1
1
1
1
1
0
0
0
0
0
1
1
1
1
1
1
0

the command line :

~/mlpack-2.2.1/build/bin/mlpack_decision_tree -t my_tree_example.csv --labels_file my_tree_labels.csv --output_model_file /tmp/my_dec_tree_model.xml

the resulting xml file :

<?xml version="1.0" encoding="UTF-8" standalone="yes" ?>
<!DOCTYPE boost_serialization>
<boost_serialization signature="serialization::archive" version="9">
<model class_id="0" tracking_level="0" version="0">
	<tree class_id="1" tracking_level="0" version="0">
		<numChildren>0</numChildren>
		<splitDimension>140157621338880</splitDimension>
		<dimensionTypeOrMajorityClass>0</dimensionTypeOrMajorityClass>
		<classProbabilities class_id="2" tracking_level="0" version="0">
			<n_rows>2</n_rows>
			<n_cols>1</n_cols>
			<n_elem>2</n_elem>
			<vec_state>1</vec_state>
			<item>0.5</item>
			<item>0.5</item>
		</classProbabilities>
	</tree>
</model>
</boost_serialization>