# C The `fit` command: mathematical details

Details of the `fit` command

In this section, the mathematical details of the workings of the `fit` command are described. This may be of interest in diagnosing its limitations, and also in understanding the various quantities that it outputs after a fit is found. This discussion must necessarily be a rather brief treatment of a large subject; for a fuller account, the reader is referred to D.S. Sivia’s *Data Analysis: A Bayesian Tutorial*.