Initial conditions for the P-Millennium simulation (Baugh et al. 2018)
at various resolution. These are all DMONLY runs in a 800^3 Mpc^3
volume with the cosmology given by Planck-13:

 Om = 0.307, Ol = 0.693, h = 0.6777, Ob = 0.0455

The ICs exist at different resolution. The Millennium simulation
(Springel 2005) has a resolution in between the 1536^3 and 3072^3
examples given here.

The ICs sizes are:

PMill-384   - 1.1 GB
PMill-768   - 8.3 GB
PMill-1536  - 163 GB
PMill-3072  - 1.3 TB

The ICs' md5 checksums are:

c6134185aaa536d695d290e7b7a75f6f  PMill-384.hdf5
f20a8c446e24444df55daaea2163f233  PMill-768.hdf5
bfaad140062f475c120002a76dd83f01  PMill-1536.hdf5
59bd72f821e5f5a117a5c2ed23056f9e  PMill-3072.hdf5
