fix tutorial 4 argument error

Author: Stephen Penny

runall_tutorial_4.sh

@@ -7,7 +7,7 @@ echo "sh runall_tutorial_4.sh <method2>"
 echo "Hybrid is analyzed and compared to <method2>"
 
 method1=Hybrid
-method2=$2
+method2=$1
 python analysis_init.py $method1
 python generate_analysis_3dEns.py
 python plot_analysis_vs_nature.py $method1