How do you send numpy arrays with metadata between processes using mpi?

mpi_goose_chase.py

"""
Run with

mpiexec -n 11 mpi_goose_chase.py
"""
from __future__ import print_function
from mpi4py import MPI
import numpy as np
import time

comm = MPI.COMM_WORLD
rank = comm.Get_rank()
size = comm.Get_size()

#initializing variables. mpi4py requires that we pass numpy objects.
dims = (2048, 2048)
dtype = np.complex128
n_reconstructions = 10

# Create tag for each process, create memory buffer
tag = [rank + 0*1j]
recv_buffer = np.zeros(dims[0]*dims[1] + len(tag), dtype=dtype)

if rank == size - 1:
    reconstruction_cube = np.zeros((n_reconstructions, dims[0], dims[1]),
                                            dtype=dtype)
    for i in range(0, size-1):
        comm.Recv(recv_buffer, MPI.ANY_SOURCE)
        process_tag = recv_buffer[:len(tag)]
        process_image = recv_buffer[len(tag):].reshape(dims)
        image_index = int(np.real(process_tag))
        reconstruction_cube[image_index, ...] = process_image

else:
    # Generate science image
    local_image = np.array(rank+np.zeros(dims) + np.zeros(dims)* 1j, dtype=dtype)

    # Ravel, add tags to the beginning
    local_tagged_image = np.concatenate([tag, local_image.ravel()])

    # all other process send their result
    comm.Send(local_tagged_image, dest=size-1)

if rank == size-1:
    print(reconstruction_cube)