cosmicjellyfish.fishermatrix.jaxcosmo_derivatives#

Derivative providers for the JAX-native observables of the jaxcosmo backend.

Two providers implement cosmicjellyfish.fishermatrix.derivatives.DerivativeProvider:

JaxAutodiffProvider differentiates the JAX observable with jax.jacfwd;
JaxFiniteDifferenceProvider applies the same finite-difference engine used by the standard CosmicJellyfish pipeline to the same JAX observable.

Having both is what makes a controlled validation possible: autodiff against finite differences of one implementation isolates the derivative method, while either of them against the legacy NumPy observable isolates the observable implementation.

Usage#

>>> from cosmicjellyfish.fishermatrix.jaxcosmo_derivatives import JaxAutodiffProvider  

The providers are stateful on purpose: the JAX observable and its compiled Jacobians are cached between calls (and are not picklable), so a fresh provider must be created in every worker process. The probes GCph + WL (photometric) and GCsp (spectroscopic) are supported; the provider picks the JAX observable from request.observables_type.

Classes

`JaxAutodiffProvider`	Exact forward-mode derivatives of the JAX observables (`jaxcosmo` backend).
`JaxFiniteDifferenceProvider`	Finite differences of the JAX observable, using the standard CosmicJellyfish engine.