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final adjustments before the hand in

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Remy Moll
2025-09-15 11:50:00 +00:00
parent 221bdcda07
commit 04598e6bb1
8 changed files with 48 additions and 27 deletions
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@@ -9,8 +9,7 @@ For each halo we require a flux profile that matches the halo properties which n
// Maybe reformulate
Since the dynamic range of accretion rates is large, the resulting parameter space rapidly expands. The computation of the profiles therefore utilizes vectorized operations to achieve reasonable runtimes.
// TODO - reformulate
Note that this introduces another "second degree" inconsistency: The flux profile attributes a radiative behavior to the halo that is motivated by its history. This is repeated for each snapshot creating possibly conflicting histories. In the case of stable halo growth this is not a problem but in the case of erratic growth (e.g. major mergers) this can lead to unphysical behavior. A more consistent approach would be to assume a more flexible mass growth model that distinguishes different regimes of growth. This would require a much more complex handling of the precomputed profiles and is beyond the scope of this work. The current approach remains a good approximation for the majority of halos.
Note that the precomputation of the profiles introduces another "second degree" inconsistency: The flux profile attributes a radiative behavior to the halo that is motivated by its history. This is repeated for each snapshot creating possibly conflicting histories. In the case of stable halo growth this is not a problem but in the case of erratic growth (e.g. major mergers) this can lead to unphysical behavior. A more consistent approach would be to assume a more flexible mass growth model that distinguishes different regimes of growth. This would require a much more complex handling of the precomputed profiles and is beyond the scope of this work. The current approach remains a good approximation for the majority of halos.
== Parallel painting of profile bins
@@ -40,4 +39,4 @@ In addition to the changes directly linked to the new accretion model we impleme
We improve the input/output handling by implementing proper `HDF5` support and caching of intermediate results. This allows for a more efficient usage of disk space and faster loading times. It also enables the resumption of interrupted simulations.
The import of data from the original #nbody simulation has been generalized to a reference class to ensure modularity and easy adaptation to other simulations. This has been part of a larger overhaul of the codebase to improve modularity and readability. #beorn aims to be a flexible framework that produces fast results that the end user can customize to reflect their parameter choices. Usability is therefore a key aspect of the code design.
A general speedup from the cumulated effect of the above changes and code optimizations results in a faster painting procedure. A contribution to that speedup comes from the usage of `Pylians` by @Pylians. It provides efficient implementations of the grid mapping of the individual particles. This additionally allows for a rigorous implementation of redshift space distortions (RSD) by utilizing the exact velocity information of each dark matter particle individually. Previous implementations of RSD in #beorn were based on approximations of the velocity field derived from the density field. The impact of RSD on the 21-cm signal has been discussed e.g. by @Ross_2021 but is not the focus of this work.
A general speedup from the cumulated effect of the above changes and code optimizations results in a faster painting procedure. A contribution to that speedup comes from the usage of the `pylians` package by @Pylians. It provides efficient implementations of the grid mapping of the individual particles. This additionally allows for a rigorous implementation of redshift space distortions (RSD) by utilizing the exact velocity information of each dark matter particle individually. Previous implementations of RSD in #beorn were based on approximations of the velocity field derived from the density field. The impact of RSD on the 21-cm signal has been discussed e.g. by @Ross_2021 but is not the focus of this work.