#! /usr/bin/env python
"""
ntp.py: Example PyROOT program which stores data
in a ROOT TNtuple which is then plotted using 
the ROOT plotting routines.


Paul Eugenio
PHZ4151C
Florida State University
April 1, 2019

"""

from __future__ import division, print_function
import numpy as np 
import ROOT 


def func( aX ):
	""" ... """
	return np.exp( -aX ) * np.sin( 3.0 * aX )**2  


# Create an instance of a Tntuple object
ntuple = ROOT.TNtuple("ntp1", "My First Ntuple", "x:y" )

# define plotting limits and step size 
xMin = 0.0
xMax =  5.0
deltaX = 0.01


for x in np.arange( xMin, xMax, deltaX ):
	# Fill the TNtuple with values for x & y
	ntuple.Fill( x, func(x) )


# Create a plot of func(x) vs x
ntuple.Draw("y:x")   

input("Enter [return] to exit")