set_iter_method_opt¶

sherpa.astro.ui.set_iter_method_opt(optname, val)¶

Set an option for the iterative-fitting scheme.

Parameters:	optname (str) – The name of the option to set. The get_iter_method_opt routine can be used to find out valid values for this argument. val – The new value for the option.
Raises:	`sherpa.utils.err.ArgumentErr` – If the `optname` argument is not recognized.

See also

get_iter_method_name(): Return the name of the iterative fitting scheme.
get_iter_method_opt(): Return one or all options for the iterative-fitting scheme.
list_iter_methods(): List the iterative fitting schemes.
set_iter_method(): Set the iterative-fitting scheme used in the fit.

Notes

The supported fields for the primini scheme are:

maxiters: The maximum number of iterations to perform.
tol: The iteration stops when the change in the best-fit statistic varies by less than this value.

The supported fields for the sigmarej scheme are:

grow: The number of points adjacent to a rejected point that should also be removed. A value of 0 means that only the discrepant point is removed whereas a value of 1 means that the two adjacent points (one lower and one higher) will also be removed.
hrej: The rejection criterion in units of sigma, for data points above the model (it must be >= 0).
lrej: The rejection criterion in units of sigma, for data points below the model (it must be >= 0).
maxiters: The maximum number of iterations to perform. If this value is 0 then the fit will run until it has converged.

Examples

Reject any points that are more than 5 sigma away from the best fit model and re-fit.

>>> set_iter_method('sigmarej')
>>> set_iter_method_opt('lrej', 5)
>>> set_iter_method_opt('hrej', 5)
>>> fit()