Synopsis
Sample the fit statistic by taking the parameter values from a Student's t-distribution.
Syntax
t_sample(num=1, dof=None, id=None, otherids=(), numcores=None) num - int, optional dof - optional id - int or str, optional otherids - sequence of int or str, optional numcores - optional
Description
For each iteration (sample), change the thawed parameters by drawing values from a Student's t-distribution, and calculate the fit statistic.
Example
The model fit to the default data set has three free parameters. The median value of the statistic calculated by `t_sample` is returned:
>>> ans = t_sample(num=10000) >>> ans.shape (1000, 4) >>> np.median(ans[:,0]) 119.9764357725326
PARAMETERS
The parameters for this function are:
| Parameter | Definition |
|---|---|
| num | The number of samples to use (default is 1). |
| dof | The number of degrees of freedom to use (the default is to use the number from the current fit). |
| id | The data set that provides the data. If not given then all data sets with an associated model are used simultaneously. |
| otherids | Other data sets to use in the calculation. |
| numcores | The number of CPU cores to use. The default is to use all the cores on the machine. |
Return value
The return value from this function is:
A NumPy array table with the first column representing the statistic and later columns the parameters used.
Bugs
See the bugs pages on the Sherpa website for an up-to-date listing of known bugs.
See Also
- contrib
- get_data_prof, get_data_prof_prefs, get_delchi_prof, get_delchi_prof_prefs, get_fit_prof, get_model_prof, get_model_prof_prefs, get_resid_prof, get_resid_prof_prefs, get_source_prof, get_source_prof_prefs, plot_chart_spectrum, plot_marx_spectrum, prof_data, prof_delchi, prof_fit, prof_fit_delchi, prof_fit_resid, prof_model, prof_resid, prof_source
- data
- get_arf_plot, get_bkg_chisqr_plot, get_bkg_delchi_plot, get_bkg_fit_plot, get_bkg_model_plot, get_bkg_plot, get_bkg_ratio_plot, get_bkg_resid_plot, get_bkg_source_plot
- info
- list_model_ids, show_bkg_model, show_bkg_source
- modeling
- add_model, add_user_pars, clean, create_model_component, delete_bkg_model, delete_model, delete_model_component, get_model, get_model_autoassign_func, 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_source, get_source_component_image, get_source_component_plot, get_source_contour, get_source_image, get_source_plot, get_xsabund, get_xscosmo, get_xsxsect, get_xsxset, image_model, image_model_component, image_source, image_source_component, integrate, link, load_table_model, load_template_interpolator, load_template_model, load_user_model, normal_sample, reset, save_model, save_source, set_bkg_model, set_bkg_source, set_full_model, set_model, set_model_autoassign_func, set_pileup_model, set_source, set_xsabund, set_xscosmo, set_xsxsect, set_xsxset, uniform_sample
- plotting
- get_cdf_plot, get_energy_flux_hist, get_pdf_plot, get_photon_flux_hist, get_pvalue_plot, get_pvalue_results, get_split_plot, plot, plot_arf, plot_bkg, plot_bkg_chisqr, plot_bkg_delchi, plot_bkg_fit, plot_bkg_fit_delchi, plot_bkg_fit_resid, plot_bkg_model, plot_bkg_ratio, plot_bkg_resid, plot_bkg_source, plot_cdf, plot_chisqr, plot_data, plot_delchi, plot_energy_flux, plot_fit, plot_fit_delchi, plot_fit_resid, plot_model, plot_model_component, plot_order, plot_pdf, plot_photon_flux, plot_pvalue, plot_ratio, plot_resid, plot_scatter, plot_source, plot_source_component, plot_trace, set_xlinear, set_xlog, set_ylinear, set_ylog
- psfs
- delete_psf, load_conv, plot_kernel
- saving
- save_delchi, save_resid
- statistics
- get_chisqr_plot, get_delchi_plot
- utilities
- calc_chisqr, calc_energy_flux, calc_model_sum, calc_photon_flux, calc_source_sum, calc_stat, eqwidth
- visualization
- contour_model, contour_ratio, contour_resid