Last modified: December 2020

URL: https://cxc.cfa.harvard.edu/sherpa/ahelp/set_method.html
AHELP for CIAO 4.13 Sherpa v1

set_method

Context: methods

Synopsis

Set the optimization method.

Syntax

set_method(meth)

meth - str

Description

The primary task of Sherpa is to fit a model M(p) to a set of observed data, where the vector p denotes the model parameters. An optimization method is one that is used to determine the vector of model parameter values, p0, for which the chosen fit statistic is minimized.


Example

>>> set_method('neldermead')

PARAMETERS

The parameter for this function is:

Parameter Definition
meth The name of the method (case is not important). The `list_methods` function returns the list of supported values.

Notes

The available methods include:

Item Definition
levmar The Levenberg-Marquardt method is an interface to the MINPACK subroutine lmdif to find the local minimum of nonlinear least squares functions of several variables by a modification of the Levenberg-Marquardt algorithm [1] .
moncar The implementation of the moncar method is based on [2] .
neldermead The implementation of the Nelder Mead Simplex direct search is based on [3] .
simplex This is another name for neldermead .

References


Bugs

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

See Also

confidence
set_conf_opt, set_covar_opt, set_proj_opt
data
set_areascal, set_arf, set_backscal, set_bkg, set_coord, set_counts, set_data, set_dep, set_exposure, set_grouping, set_quality, set_rmf, set_staterror, set_syserror
filtering
set_filter
methods
gridsearch, levmar, list_iter_methods, list_methods, moncar, neldermead, set_iter_method, set_iter_method_opt, set_method_opt
modeling
get_par, get_xsabund, get_xscosmo, get_xsxsect, get_xsxset, set_bkg_model, set_bkg_source, set_full_model, set_model, set_par, set_pileup_model, set_source, set_xsabund, set_xscosmo, set_xsxsect, set_xsxset
statistics
set_prior, set_sampler, set_sampler_opt, set_stat
utilities
set_analysis, set_default_id
visualization
image_setregion