Synopsis
Return the data calculated by the last plot_pvalue call.
Syntax
get_pvalue_results()
Description
The `get_pvalue_results` function returns the likelihood ratio test results computed by the `plot_pvalue` command, which compares fits of the null model to fits of the alternative model using faked data with Poisson noise. The likelihood ratio based on the observed data is returned, along with the p-value, used to reject or accept the null model.
Example
Return the results of the last pvalue analysis and display the results - first using the `format` method, which provides a summary of the data, and then a look at the individual fields in the returned object. The last call displays the contents of one of the fields ( `ppp` ).
>>> res = get_pvalue_results() >>> print(res.format()) >>> print(res) >>> print(res.ppp)
PARAMETERS
This function has no parameters
Return value
The return value from this function is:
plot -- If `plot_pvalue` or `get_pvalue_plot` have been called then the return value is a `sherpa.sim.simulate.LikelihoodRatioResults` instance, otherwise `None` is returned.
Notes
The fields of the returned ( `LikelihoodRatioResults` ) object are:
Item | Definition |
---|---|
ratios | The calculated likelihood ratio for each iteration. |
stats | The calculated fit statistics for each iteration, stored as the null model and then the alt model in a nsim by 2 array. |
samples | The parameter samples array for each simulation, stored in a nsim by npar array. |
lr | The likelihood ratio of the observed data for the null and alternate models. |
ppp | The p value of the observed data for the null and alternate models. |
null | The fit statistic of the null model on the observed data. |
alt | The fit statistic of the alternate model on the observed data. |
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, t_sample, uniform_sample
- plotting
- get_cdf_plot, get_energy_flux_hist, get_pdf_plot, get_photon_flux_hist, get_pvalue_plot, 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