Source code for GUIBRUSHR.Retrieval.ExofastMCMC.StructReturnExofast

"""
Module containing the StructReturnExofast class for MCMC return data structure.

This module defines a data structure used to store and manage the results
from Exofast MCMC (Markov Chain Monte Carlo) computations.
"""




class StructReturnExofast:
    """
    Data structure for storing Exofast MCMC return values.

    This class encapsulates the results from an Exofast MCMC run, including
    acceptance statistics, parameters, log-likelihood values, and log-prior values.
    """

    # Class attributes initialized to None (default values)
    naccept = None
    oldpars = None
    old_lhood = None  # IDL: chi2 (was misnamed; this is log-likelihood, higher = better)
    # IDL: 'determinant' — renamed log_prior to reflect true semantics
    # (log of Gaussian prior product; was computed in linear space in IDL,
    # causing underflow; stored in log-space here for numerical stability)
    old_log_prior = None



    def __init__(self, naccept, pars, lhood, log_prior):
        """
        Initialize the StructReturnExofast instance.

        Args:
            naccept: Number of accepted MCMC steps
            pars: Current parameter values
            lhood: Current log-likelihood value  # IDL: chi2
            log_prior: Log of the Gaussian prior product — IDL called this 'determinant'
        """
        # Store the acceptance count
        self.naccept = naccept

        # Store current parameter values
        self.pars = pars

        # Store current log-likelihood value (IDL: chi2 — renamed; higher = better)
        self.lhood = lhood  # IDL: chi2

        # IDL: self.det = det  (product of Gaussian priors, underflows for N≳150 params)
        # Now stored as log sum: log_prior = Σ -0.5*((θ-μ)/σ)², never underflows
        self.log_prior = log_prior