Algorithm 1 First sequential time ($\alpha$)

1: from mpi4py import MPI  2: import numpy as np  3: from PIL import Image  4: from decimal import *  5: comm=MPI.COMM_WORLD  6: size=comm.Get_size()        # Number of processors  7: rank=comm.Get_rank()       # Processor ID  8: if rank == 0:  9: imagen=Image.open(’image.png’)    # Read original image 10: imagen=np.array(imagen)      # Convert the object image into an array 11: ren=imagen.shape[0]       # Size of the array (rows) 12: col=imagen.shape[1]       # Size of the array (cols) 13: cap=imagen.shape[2] 14: n_ren=np.int(ren/size)            # Resize the array 15: foto=np.reshape(imagen,(size,n_ren,col,cap))   # for scattering data