Feature/baryons hmcode

[nikosarcevic]

In this PR I have ported out HMCode baryons into baryons module so it can be called in a similar manner to other baryon base modules.

To do so, I have used the existing hook to HMCode whihc is via camb call within the Cosmology object -- but wrapped in such a way that emulates the convention we want defined inside baryons_base.

One thing that was tricky is to ensure that the cosmology defined is always the cosmology object with camb BUT doing internal chekcs there is no baryonification already applied -- this is solved.

(side note: I can do the same for bacco and I think we should so that all of our baryon modules are called in the same way)

This PR adds:

• utility/helper functions defined inside pyccl/baryons/mead20_hmcode/mead20_utils.py

• pyccl/baryons/mead20.py which is the main script (kept pretty lightweight and readable) where BaryonsMead20 submodule is defined

• corresponding unit tests

• example notebooks (inside the pyccl/baryons/mead20_hmcode/ dir:

  • baryon_modules: a copy of the existing notebooks where we compare different baryon models available in ccl. i also compare the new Mead20 method to the "standard via Cosmology object" method
  • baryons_mead20.ipynb which just illustrates how to access different avaialble model parameters and how they impact the power spectrum

  locally unit tests are passing, linting is healthy

[coveralls]

Pull Request Test Coverage Report for Build 21349264080

Details

• 155 of 163 (95.09%) changed or added relevant lines in 3 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.06%) to 97.408%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
pyccl/baryons/mead20_hmcode/mead20_utils.py	88	96	91.67%

Totals
Change from base Build 21003793779:	-0.06%
Covered Lines:	6727
Relevant Lines:	6906

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💛 - Coveralls