Last modified: December 2020

URL: https://cxc.cfa.harvard.edu/sherpa/ahelp/get_prior.html
Jump to: Description · Example · PARAMETERS · Bugs · See Also


AHELP for CIAO 4.13 Sherpa v1

get_prior

Context: statistics

Synopsis

Return the prior function for a parameter (MCMC).

Syntax

get_prior(par)

par - a `Parameter` instance

Description

The default behavior of the pyBLoCXS MCMC sampler (run by the `get_draws` function) is to use a flat prior for each parameter. The `get_prior` routine finds the current prior assigned to a parameter, and `set_prior` is used to change it.


Example

>>> prior = get_prior(bgnd.c0)
>>> print(prior)

PARAMETERS

The parameter for this function is:

Parameter Definition
par A parameter of a model instance.

Return value

The return value from this function is:

The parameter prior set by a previous call to `set_prior` . This may be a function or model instance.


Bugs

See the bugs pages on the Sherpa website for an up-to-date listing of known bugs.

See Also

confidence
get_conf, get_conf_results, get_covar, get_covar_opt, get_covar_results, get_covariance_results, get_int_proj, get_int_unc, get_proj, get_proj_opt, get_proj_results, get_projection_results, get_reg_proj, get_reg_unc
contrib
get_chart_spectrum, get_marx_spectrum
data
get_areascal, get_arf, get_arf_plot, get_axes, get_backscal, get_bkg, get_bkg_arf, get_bkg_chisqr_plot, get_bkg_delchi_plot, get_bkg_fit_plot, get_bkg_model, get_bkg_model_plot, get_bkg_plot, get_bkg_ratio_plot, get_bkg_resid_plot, get_bkg_rmf, get_bkg_scale, get_bkg_source, get_bkg_source_plot, get_coord, get_counts, get_data, get_data_contour, get_data_contour_prefs, get_data_image, get_data_plot, get_data_plot_prefs, get_dep, get_dims, get_error, get_exposure, get_grouping, get_indep, get_quality, get_rmf, get_specresp, get_staterror, get_syserror
filtering
get_filter
fitting
calc_stat_info, get_stat_info
info
get_default_id, list_stats
methods
get_draws, get_iter_method_name, get_iter_method_opt, get_method, get_method_name, get_method_opt
modeling
get_model, get_model_component, get_model_component_image, get_model_component_plot, get_model_plot, get_num_par, get_num_par_frozen, get_num_par_thawed, get_order_plot, get_par, get_pileup_model, get_response, get_source, get_source_component_image, get_source_component_plot, get_source_contour, get_source_image, get_source_plot, image_source
plotting
get_split_plot
psfs
get_psf, get_psf_contour, get_psf_image, get_psf_plot
statistics
cash, chi2constvar, chi2datavar, chi2gehrels, chi2modvar, chi2xspecvar, chisquare, cstat, get_chisqr_plot, get_delchi_plot, get_sampler, get_stat, get_stat_name, leastsq, list_priors, set_prior, set_sampler, set_stat, wstat
utilities
get_analysis, get_rate
visualization
image_getregion