From ae4e057c284b5191616782524fc7dc7e479decbe Mon Sep 17 00:00:00 2001 From: Lehman Garrison Date: Thu, 12 Jan 2023 11:22:31 -0500 Subject: [PATCH] Update data-products.rst Add notes about ph098 --- docs/data-products.rst | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/docs/data-products.rst b/docs/data-products.rst index dc7681b1..22f663c0 100644 --- a/docs/data-products.rst +++ b/docs/data-products.rst @@ -453,3 +453,13 @@ Late-time particle samples (e.g. from halo catalogs) can be connected to their location in the ICs via the PID. Pass ``unpack_bits="lagr_pos"`` or ``unpack_bits="lagr_idx"`` to the :doc:`CompaSOHaloCatalog constructor `, or to the ``load`` parameter of :doc:`read_asdf `. + +Fixed-and-paired ICs +~~~~~~~~~~~~~~~~~~~~ +The ``fixedbase`` simulations use fixed-amplitude initial conditions, with ``ph098`` the +inverse of ``ph099``. This inversion was implemented with a flag to Abacus that flipped +the Zel'dovich displacements as they were ingested; the actual IC files were the same for +``ph098`` and ``ph099``. As a consequence, the IC data products are identical for ``ph098`` +and ``ph099``, even though one might expect them to be inverted. We recommend users of +``ph098`` invert the density field and displacements themselves, which in both cases is +as simple as multiplying the fields by :math:`-1`.