local_frame_key

ell1fit.mcmc_utils.local_frame_key(parameter_names, factors, initial_values)

Fingerprint the local coordinate frame a chain’s samples are written in.

A stored sample is a local coordinate: the physical value is sample * factor + initial. Change either the factor – which ell1fit.scaling.get_factors() derives from the data, the parfile and any --prior – or the initial value the optimizer started from, and the same stored number now means a different frequency, epoch or axis. A chain resumed across such a change is not a chain of anything, and says so only through an acceptance rate that quietly collapses.

Nothing else about the run belongs in the key. A different likelihood, move set or event selection still explores the same coordinates, and safe_run_sampler() already documents that resuming under new moves is allowed.

Parameters:

parameter_namessequence of str

Fitted parameter names, in the order the coordinates are stored.

factorssequence of float

Local-to-physical scale of each parameter.

initial_valuessequence of float

Physical value each parameter’s local zero corresponds to.

Returns:

str

A short hex digest, stable across runs and machines.