def mpi_local_and_global_index(begin_idx, local_n):
	""" This function will return a list of tuples with a local index and the global index of the given value of begin index and local chunk size for mpi. The reason why we need this is because the we can run a for loop with two indicies if they are provided in a tuple form.\n
	Input:
	------------
	begin_index : 	of the lat/lon running on the local processor when using mpi
	local_n		:	the chunk size of the array we want to run on that processor

	Output:	
	-----------
	result		:	a list of tuple (local_idx,global_idx)
	"""
	local_idx=	0
	result	=	[]
	for i in range(local_n):
		result.append((local_idx,begin_idx))
		begin_idx	+=	1
		local_idx	+=	1
	return result