Interface

At its heart, the likelihood is a straightforward function that takes a set of parameters and CMB spectra and returns the log likelihood value. Therefore, the interface is rather simple and allows candl to be used with a variety of other software.

The most common use case is to interface the likelihood with a theory code, i.e. a code that provides CMB spectra given a set of cosmological parameters, in order to create a function that moves from parameters to the log likelihood in one step. The next step, is then to explore this function using a sampler, which explores the parameter space and finds the best-fit point or returns samples from the posterior distribution. The respective pages contain more information on how both of these tasks are achieved. A set of ready-made solutions for different popular software packages is provided in the interface module (see the documentation for details).

Tip

In addition to tools to interface the likelihood with theory codes and samplers separately, we also provide tools to interface CosmoPower, CosmoPower-JAX, and Capse.jl emulators with Cobaya.