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Last modified: December 2010

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AHELP for CIAO 4.3 Sherpa v1


Context: confidence


Set the options for confidence


set_conf_opt( name, val )


The set_conf_opt command allows the user to set the options for the confidence parameter estimation method (see "ahelp conf").

  • name - confidence option name
  • val - value for the option

A list of the available options is returned by the get_conf_opt command (see "ahelp get_conf"), e.g.:

sherpa> print(get_conf_opt())
{'verbose': False, 'openinterval': False, 'max_rstat': 3, 'maxiters': 200, 'soft_limits':False, 'eps': 0.01, 'fast': True, 'maxfits': 5, 'remin': 0.01, 'tol': 0.20000000000000001,
 'sigma': 1, 'parallel': True}
  • eps - precision of resulting limits, default=0.01
  • fast - the fit optimization method is automatically switched to a faster option to reduce the time per fit; default=True
  • max_rstat - maximum possible value of the reduced statistic, default=3
  • maxfits - maximum number of tries to fit the parameter space, default=5
  • maxiters- maximum number of tries to bracket desired limits, before returning, default=200
  • openinterval - how the confidence function should behave when it cannot locate the root within the open interval; see "ahelp conf" for a detailed explanation; default=False
  • parallel - switch which allows confidence to be run as a parallel process; default=True
  • remin - if during search, a new fit statistic is found that is smaller than original best fit, the difference between new and original statistics must be greater than this value, default=0.01
  • sigma - to get 1, 2, or 3-sigma limits, default=1
  • soft_limits - a switch which allows the search to go all the way out to the hard parameter limits; if switched on, the search will be restricted to occur within the soft limits, which can be changed by the user, default=False
  • tol - tolerance for the fit, default=0.20000000000000001
  • verbose - print information to the screen?; default=False


sherpa> set_conf_opt("maxiters", 400)
sherpa> set_conf_opt("sigma", 3)

Set the value of the "maxiters" confidence option to 400 and the "sigma" value to 3 for the next run of the confidence command.


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

See Also

conf, covariance, get_conf, get_covar, get_int_proj, get_int_unc, get_proj, get_reg_proj, get_reg_unc, int_proj, int_unc, projection, reg_proj, reg_unc, set_covar_opt, set_proj_opt
set_areascal, set_arf, set_backscal, set_bkg, set_coord, set_counts, set_data, set_exposure, set_grouping, set_quality, set_rmf, set_staterror, set_syserror
set_iter_method, set_iter_method_opt, set_method, set_method_opt
get_par, set_bkg_model, set_full_model, set_par, set_pileup_model, set_source, set_xsabund, set_xscosmo, set_xsxsect, set_xsxset
set_analysis, set_default_id

Last modified: December 2010
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