2.3.3.3.102. NXfit_function

Status:

base class (contribution), extends NXobject

Description:

This describes a fit function that is used to fit data to any functional form. ...

This describes a fit function that is used to fit data to any functional form.

A fit function is used to describe a set of data $y_k,k=1...M$, which are collected as a function of one or more independent variables $x$ at the points $x_k$. The fit function $f$ describes these data in an approximate way as $y_k\approx f(a_0,...a_n,x_k)$, where $a_i,i=0...n$ are the fit parameters (which are stored the instances of NXfit_parameter).

Symbols:

No symbol table

Groups cited:

NXparameters

Structure:

function_type: (optional) NX_CHAR

Type of function used. ...

Type of function used.

Examples include “Gaussian” and “Lorentzian”. In case a complicated functions, the the functional form of the function should be given by the formula_description field . The user is also encouraged to use the description field for describing the fit function in a human-readable way.

Application definitions may limit the allowed fit functions by using an enumeration for the function_type field.

description: (optional) NX_CHAR

Human-readable short description of this fit function. ...

Human-readable short description of this fit function. Software tools may use this field to write their local description of the fit function.

formula_description: (optional) NX_CHAR

Description of the mathematical formula of the function, taking into account t ...

Description of the mathematical formula of the function, taking into account the instances of TERM in fit_parameters.

fit_parameters: (optional) NXparameters ⤆

TERM: (optional) NX_CHAR {units=NX_ANY}

A parameter for a fit function. ...

A parameter for a fit function. This would typically be a variable that is optimized in a fit.

@description: (optional) NX_CHAR

A description of what this parameter represents.

@fixed: (optional) NX_BOOLEAN

If the parameter is held constant, then this attribute should be True.

@min_value: (optional) NX_NUMBER

The minimal value of the parameter, to be used as a constraint during fitting.

@max_value: (optional) NX_NUMBER

The maximal value of the parameter, to be used as a constraint during fitting.

Hypertext Anchors

List of hypertext anchors for all groups, fields, attributes, and links defined in this class.

• /NXfit_function/description-field

• /NXfit_function/fit_parameters-group

• /NXfit_function/fit_parameters/TERM-field

• /NXfit_function/fit_parameters/TERM@description-attribute

• /NXfit_function/fit_parameters/TERM@fixed-attribute

• /NXfit_function/fit_parameters/TERM@max_value-attribute

• /NXfit_function/fit_parameters/TERM@min_value-attribute

• /NXfit_function/formula_description-field

• /NXfit_function/function_type-field

NXDL Source:

https://github.com/FAIRmat-NFDI/nexus_definitions/tree/fairmat/contributed_definitions/NXfit_function.nxdl.xml