flow.steady.steady_populations

flow.steady.steady_populations(step_fn, options, theta, f0)

The converged populations, differentiated through the fixed point.

Forward, this is :func:iterate_to_steady. Backward, it is the adjoint system of the converged equation – the initial guess f0 therefore receives a zero cotangent, which is the honest answer: move the guess and the converged state does not move.

Parameters

Name Type Description Default
step_fn Callable (f, theta) -> f, one lattice time. Static; passed as a nondiff_argnum, so a fresh closure per call defeats caching. required
options SteadyOptions Convergence settings, static and hashable. required
theta Any The differentiable parameters (any pytree step_fn accepts). required
f0 jax.Array Initial populations. required

Returns

Name Type Description
jax.Array The converged populations, (19, NX, NY, NZ).