def open_file(filename):
	"""
	Args: filename (string)
	Return: position(List), potential(List)

	This function reads the data from the given file.
	"""
	position = []
	potential = []
	file = open(filename, 'r')
	for line in file:
		if(line[0] != '#'):
			data = line.split()
			position.append(float(data[0]))
			potential.append(float(data[1]))
	file.close()
	return position, potential