import h5py
import numpy as np

f=h5py.File('small.hdf5','w')

for g in ['inc0','inc1']:
     f.create_group(g)
     f[g].create_dataset('T',data=np.random.rand(2,3,4,3,3))
     M = np.array([[0,1],[4,5]]).reshape(2,2)
     M_field = np.broadcast_to(M,(2,3,4,2,2)).copy()
     M_field[1,2,3]=-20.
     f[g].create_dataset('M',data=M_field)
     f[g].create_dataset('u',data=np.zeros(3*4*5*3).reshape(3,4,5,3))

f.close()