Copying arrays in update field

[Lun4m]

HyMD/hymd/field.py

Lines 39 to 63 in d3aff97

	for t in range(config.n_types):
	hamiltonian.v_ext[t](phi).r2c(out=v_ext_fourier[0])
	v_ext_fourier[0].apply(hamiltonian.H, out=Ellipsis)
	np.copyto(
	v_ext_fourier[1].value, v_ext_fourier[0].value, casting="no", where=True
	)
	np.copyto(
	v_ext_fourier[2].value, v_ext_fourier[0].value, casting="no", where=True
	)
	if compute_potential:
	np.copyto(
	v_ext_fourier[3].value, v_ext_fourier[0].value, casting="no", where=True
	)
	# Differentiate the external potential in fourier space
	for d in range(3):
	def force_transfer_function(k, v, d=d):
	return -k[d] * 1j * v
	v_ext_fourier[d].apply(force_transfer_function, out=Ellipsis)
	v_ext_fourier[d].c2r(out=force_mesh[t][d])
	if compute_potential:
	v_ext_fourier[3].c2r(out=v_ext[t])

Can this snippet above be simplified with the following? Why do we need to copy arrays?

for t in range(config.n_types):
    hamiltonian.v_ext[t](phi).r2c(out=v_ext_fourier[t])
    v_ext_fourier[t].apply(hamiltonian.H, out=Ellipsis) 

    for d in range(3): 
        def force_transfer_function(k, v, d=d): 
            return -k[d] * 1j * v

        force_mesh_fourier = v_ext_fourier[t].apply(force_transfer_function) 
        force_mesh_fourier.c2r(out=force_mesh[t][d])

    if compute_potential: 
        v_ext_fourier.c2r(out=v_ext[t]) 

where v_ext_fourier is simply

v_ext_fourier = [pm.create("complex", value=0.0) for _ in range(config.n_types)]