Last modified: December 2023

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AHELP for CIAO 4.16 Sherpa


Context: modeling


Add parameter information to a user model.


add_user_pars(modelname, parnames, parvals=None, parmins=None,
parmaxs=None, parunits=None, parfrozen=None)

modelname - str
parnames - array of str
parvals - array of number, optional
parmins - array of number, optional
parmaxs - array of number, optional
parunits - array of str, optional
parfrozen - array of bool, optional


Example 1

Create a user model for the function `profile` called "myprof", which has two parameters called "core" and "ampl", both of which will start with a value of 0.

>>> load_user_model(profile, "myprof")
>>> add_user_pars("myprof", ["core", "ampl"])

Example 2

Set the starting values, minimum values, and whether or not the parameter is frozen by default, for the "prof" model:

>>> pnames = ["core", "ampl", "intflag"]
>>> pvals = [10, 200, 1]
>>> pmins = [0.01, 0, 0]
>>> pfreeze = [False, False, True]
>>> add_user_pars("prof", pnames, pvals,
...               parmins=pmins, parfrozen=pfreeze)


The parameters for this function are:

Parameter Definition
modelname The name of the user model (created by `load_user_model` ).
parnames The names of the parameters. The order of all the parameter arrays must match that expected by the model function (the first argument to `load_user_model` ).
parvals The default values of the parameters. If not given each parameter is set to 0.
parmins The minimum values of the parameters (hard limit). The default value is -3.40282e+38.
parmaxs The maximum values of the parameters (hard limit). The default value is 3.40282e+38.
parunits The units of the parameters. This is only used in screen output (i.e. is informational in nature).
parfrozen Should each parameter be frozen. The default is that all parameters are thawed.


The parameters must be specified in the order that the function expects. That is, if the function has two parameters, pars[0]='slope' and pars[1]='y_intercept', then the call to add_user_pars must use the order ["slope", "y_intercept"].


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

See Also

dataspace1d, dataspace2d, datastack, fake, 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, load_arf, load_arrays, load_ascii, load_bkg, load_bkg_arf, load_bkg_rmf, load_data, load_grouping, load_image, load_multi_arfs, load_multi_rmfs, load_pha, load_quality, load_rmf, load_staterror, load_syserror, load_table, pack_image, pack_pha, pack_table, unpack_arf, unpack_arrays, unpack_ascii, unpack_bkg, unpack_data, unpack_image, unpack_pha, unpack_rmf, unpack_table
get_default_id, list_bkg_ids, list_data_ids, list_model_ids, show_bkg_model, show_bkg_source
add_model, 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
get_cdf_plot, get_pdf_plot, get_pvalue_plot, get_pvalue_results, plot_cdf, plot_model, plot_model_component, plot_pdf, plot_pvalue, plot_scatter, plot_source, plot_source_component, plot_trace
delete_psf, load_conv
save_arrays, save_data, save_delchi, save_error, save_filter, save_grouping, save_image, save_pha, save_quality, save_resid, save_staterror, save_syserror, save_table
calc_chisqr, calc_energy_flux, calc_model_sum, calc_photon_flux, calc_source_sum, calc_stat, eqwidth
contour_model, contour_ratio, contour_resid