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IqtFitMultiple v1

Summary

Fits an *_iqt file generated by I(Q,t).

Properties

Name

Direction

Type

Default

Description

InputWorkspace

Input

MatrixWorkspace

Mandatory

The _iqt.nxs InputWorkspace used by the algorithm

Function

InOut

Function

Mandatory

The function to use in fitting

FitType

Input

string

The type of fit being carried out

StartX

Input

number

0

The first value for X

EndX

Input

number

0.2

The last value for X

SpecMin

Input

number

0

Minimum spectra in the workspace to fit

SpecMax

Input

number

1

Maximum spectra in the workspace to fit

Minimizer

Input

string

Levenberg-Marquardt

The minimizer to use in fitting

MaxIterations

Input

number

500

The Maximum number of iterations for the fit

ConstrainIntensities

Input

boolean

False

If the Intensities should be constrained during the fit

ExtractMembers

Input

boolean

False

If true, then each member of the fit will be extracted, into their own workspace. These workspaces will have a histogram for each spectrum (Q-value) and will be grouped.

OutputResultWorkspace

Output

MatrixWorkspace

Mandatory

The output workspace containing the results of the fit data

OutputParameterWorkspace

Output

TableWorkspace

Mandatory

The output workspace containing the parameters for each fit

OutputWorkspaceGroup

Output

WorkspaceGroup

Mandatory

The OutputWorkspace group Data, Calc and Diff, values for the fit of each spectra

Description

Fits an *_iqt file generated by Iqt using one of the specified functions. The functions available are either one or two exponentials (\(Intensity \times exp[-(x/\tau)]\)), a stretched exponential (\(Intensity \times exp[-(x/\tau)]\beta\)) or a combination of both an exponential and stretched exponential.

This routine was originally part of the MODES package.

Workflow

../_images/IqtFitMultiple-v1_wkflw.svg

Usage

Example - Running IqtFitMultiple on an reduced workspace.

#Load in iqt data
input_ws = Load(Filename='iris26176_graphite002_iqt.nxs')
function = r'name=LinearBackground,A0=0.027668,A1=0,ties=(A1=0);name=UserFunction,Formula=Intensity*exp(-(x/Tau)^Beta),Intensity=0.972332,Tau=0.0247558,Beta=1;ties=(f1.Intensity=1-f0.A0)'

#run IqtFitMultiple
result, params, fit_group = IqtFitMultiple(InputWorkspace=input_ws, Function=function, FitType='1S_s', StartX=0, EndX=0.2, SpecMin=0, SpecMax=16)

Categories: AlgorithmIndex | Workflow\MIDAS

Source

Python: IqtFitMultiple.py