get_covar

sherpa.astro.ui.get_covar()

Return the covariance estimation object.

Returns:

covar

Return type:

object

See also

covar

Estimate parameter confidence intervals using the covariance method.

get_covar_opt

Return one or all of the options for the covariance method.

set_covar_opt

Set an option of the covar estimation object.

Notes

The attributes of the covariance object include:

eps

The precision of the calculated limits. The default is 0.01.

maxiters

The maximum number of iterations allowed before stopping for that parameter. The default is 200.

sigma

What is the error limit being calculated. The default is 1.

soft_limits

Should the search be restricted to the soft limits of the parameters (True), or can parameter values go out all the way to the hard limits if necessary (False). The default is False

Examples

>>> print(get_covar())
name        = covariance
sigma       = 1
maxiters    = 200
soft_limits = False
eps         = 0.01

Change the sigma field to 1.9.

>>> cv = get_covar()
>>> cv.sigma = 1.6