2.3.3.3.122. 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

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.

NXDL Source:

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