rxmc.likelihood_model.Chi2LikelihoodModel#

class rxmc.likelihood_model.Chi2LikelihoodModel[source]#

Bases: LikelihoodModel

A LikelihoodModel that returns the negative half of the chi-squared statistic for the log likelihood, ignoring the log determinant term. This is useful for doing chi2 minimization without computing the full log likelihood.

__init__()[source]#

Initializes the LikelihoodModel, optionally with a fractional uncorrelated error.

Methods

__init__()

Initializes the LikelihoodModel, optionally with a fractional uncorrelated error.

chi2(observation, ym)

Calculate the generalised chi-squared statistic.

covariance(observation, ym)

Default covariance model.

log_likelihood(observation, ym)

Returns -1/2 Chi2 only, ignoring the log determinant term.

residual(observation, ym)

Return the residual observation.y - ym.
log_likelihood(observation: Observation, ym: ndarray)[source]#

Returns -1/2 Chi2 only, ignoring the log determinant term.

Parameters:

  • ym (np.ndarray) – Model prediction for the observation.

  • observation (Observation) – The observation object containing the observed data.

Returns:

float