gh-492: Adding running of the spectral index and curvature emulators

[ivansladoljev]

🚀 Pull Request Checklist

✅ Summary

Adds curvature and running spectral index emulators to the CosmoPowerJAX module, and adds alpha_s support to CAMBBackground.

🔄 Changes per file

• camb_cosmology.py

CAMBBackground.__init__: added alpha_s: float = 0.0 (optional, after N_ur)
CAMBBackground: added self.alpha_s = alpha_s and passes it to InitPower.set_params(..., nrun=self.alpha_s)
CAMBNonLinearPerturbations.__init__: added linearperturbations parameter (typed Optional["CAMBLinearPerturbations"])

• class_cosmology.py
CLASSBackground.__init__: added **kwargs to accept (and ignore) CAMB-specific params like alpha_s

• 'jax_cosmology.py`

JAXBackground.__init__: added **kwargs for the same reason

• cosmopower_jax_cosmology.py

Added support for 2-degenerate-neutrino models (N_mnu=2) for w0waCDM/wCDM/LCDM
Updated Zenodo URL to new record
Renamed emulator .npz filenames (e.g. w0wa-linear-spectra.npz → w0wa-linear.npz)
Added CosmoPowerJAXCurvaturePerturbations and CosmoPowerJAXRunningIndexPerturbations classes
Added k_modes_curvature_path

• docs/code_structure/background.md

Updated CosmoPowerJAX description (linear+nonlinear), added emulator class table, added alpha_s=0.0 to example

• docs/code_structure/summary_statistics.md
  Removed broken #performance-tips link from warning admonition; added ## Performance Tips section below it

• tests/test_baccoemu.py

Added alpha_s=0.0 to CAMBBackground fixture

• tests/test_bnt.py

Added alpha_s=0.0 to _cosmo_pars and to the required attributes set

• tests/test_camb_cosmology.py

Added alpha_s=0.0 to all CAMBBackground instantiations
Added linearperturbations=None (or None positionally) to all CAMBNonLinearPerturbations calls
Added new test test_camb_background_running_spectral_index

• tests/test_camb_photo_z0_compatibility.py

Added alpha_s=0.0 to CAMBBackground; added None to CAMBNonLinearPerturbations call
tests/test_cmb.py

Added alpha_s=0.0 to CAMBBackground; added None to CAMBNonLinearPerturbations calls
tests/test_cosmology_background.py`

Added alpha_s=0.0 to _cosmo_pars; removed alpha_s from attributes_required set (since it was removed from the protocol)

• tests/test_cosmopower_jax_emulators.py

Added alpha_s=0.0 to DummyBackground
Added background_w0wa_2degen fixture
Added imports for CosmoPowerJAXCurvaturePerturbations and CosmoPowerJAXRunningIndexPerturbations

🛠 How to Test

pytest tests/test_cosmopower_jax_emulators.py -v
pytest tests/test_camb_cosmology.py -v

📝 Documentation

• This PR updates documentation
• This PR does not require documentation changes
• Issue created for documentation update: Don't forget to link the task!

🏗 Related Issues

Resolves #492

---

✅ PR Checklist for Developers

• I have titled this PR before merging as "gh-#:", where "#" represents the task it closes
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✅ PR Checklist for Reviewers

• The next PR targets the correct branch
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• Check that the code can still be installed if new packages are imported
• If necessary, the notebooks in the playground will be updated in a corresponding follow-up PR
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[gcanasherrera]

Hi @ivansladoljev,

• Conflicts might need to be resolved
• Also, is there a follow up playground to update the notebooks and scripts?

[ivansladoljev]

Hi @ivansladoljev,

• Conflicts might need to be resolved
• Also, is there a follow up playground to update the notebooks and scripts?

Ok, I will update and solve any new conflicts that have arisen.

Regarding the playground, there is an initial PR for cosmopower in playground [https://github.com/cloe-org/playground/pull/140]. Maybe once that is merged, I can update it with new emulators (or we can do it all in one big PR, since there is not a lot of difference between everything).

[gcanasherrera]

Sure, we can update that one later, but also, we need to update anything related to CAMB and CLASS as you are adding an extra parameter there :)

[ivansladoljev]

Sure, we can update that one later, but also, we need to update anything related to CAMB and CLASS as you are adding an extra parameter there :)

Yes. This PR addresses all the tests for CAMB/CLASS in cloelib, but for playground and cloelike there will be other PR's.

For cloelike, there is already a PR for fixing nonlinear perturbations (just the cosmetic one) cloe-org/cloelike#121, and the one for alpha_s cloe-org/cloelike#123.

For the playground there are fixes for nonlinear perturbations (cloe-org/playground#138). which are kind of URGENT, since we merged the fixes into cloelib.
I can add the alpha_s changes to the overall cosmopower notebook PR, same as here (cloe-org/playground#140).