plima.backends.ccl.nla#

CCL backend helpers for NLA intrinsic alignment bias inputs.

This module connects PLIMA NLA amplitude models to the IA bias tuple expected by CCL weak lensing tracers.

CCL weak lensing tracers expect the conventional user facing A_IA(z) amplitude when use_A_ia=True. CCL then applies the NLA normalization and minus sign internally. Therefore this backend returns the physical PLIMA amplitude directly and does not flip its sign.

Functions

make_ccl_nla_ia_bias(z, *[, amplitude, a_ia])

Return a CCL IA bias tuple for NLA.
plima.backends.ccl.nla.make_ccl_nla_ia_bias(z, *, amplitude=None, a_ia=1.0)[source]#

Return a CCL IA bias tuple for NLA.

This backend follows the PLIMA user-facing convention that positive A_IA corresponds to a positive NLA amplitude. The returned ia_bias is the conventional A_IA(z) tuple expected by CCL when WeakLensingTracer(..., use_A_ia=True) is used.

Parameters:

  • z (ArrayLike) – Redshift values where the IA bias should be sampled.

  • amplitude (ArrayLike | float | None) – Optional precomputed positive physical NLA amplitude evaluated at z. If None, the amplitude is computed from nla_amplitude.

  • a_ia (float) – Positive physical NLA amplitude normalization used when amplitude is None.

Returns:

Redshift values and conventional CCL A_IA(z) values sampled on the same grid.

Return type:

tuple[NDArray[float64], NDArray[float64]]