neg_log_likelihood

ctapipe.image.neg_log_likelihood(image, prediction, spe_width, pedestal, prediction_safety=20.0)

Safe implementation of the poissonian likelihood implementation, adaptively switches between the full solution and the gaussian approx depending on the prediction. Prediction safety parameter determines cross over point between the two solutions.

Parameters

image: ndarray

Pixel amplitudes from image (\(s\)).

prediction: ndarray

Predicted pixel amplitudes from model (\(μ\)).

spe_width: ndarray

Width of single p.e. peak (\(σ_γ\)).

pedestal: ndarray

Width of pedestal (\(σ_p\)).

prediction_safety: float

Decision point to choose between poissonian likelihood and gaussian approximation.

Returns

float