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            fit: fit data

Find the best fit model parameters for the current data by minimizing the current statistic.

Syntax:           fit  <fit method parameters>

The arguments to fit depend on the fitting method currently in use. See the method command for details. Output from the fit command also depends on the fitting method currently in use.

Examples:

Using the Levenberg-Marquadt algorithm, the parameters accepted are the maximum number of iterations before the user is prompted, and the “critical delta,” which is the change in the statistic between iterations less than which the fit is deemed to have converged.

 

XSPEC12> fit

//Fit with the default number of iterations and critical delta

// chi-squared.

XSPEC12> fit 60

//Fit with 60 as the number of iterations.

XSPEC12> fit  50 1.e-5

//Fit with 1.e-5 as the critical delta.