RefinePowderDiffProfileSeq dialog.
Table of Contents
| Name | Direction | Type | Default | Description |
|---|---|---|---|---|
| InputWorkspace | Input | MatrixWorkspace | Name of data workspace containing the diffraction pattern in .prf file. | |
| WorkspaceIndex | Input | number | 0 | Spectrum (workspace index starting from 0) of the data to refine against in input workspace. |
| SeqControlInfoWorkspace | InOut | TableWorkspace | Name of table workspace containing sequential refinement information. | |
| InputProfileWorkspace | Input | TableWorkspace | Name of table workspace containing starting profile parameters. | |
| InputBraggPeaksWorkspace | Input | TableWorkspace | Name of table workspace containing a list of reflections. | |
| InputBackgroundParameterWorkspace | Input | TableWorkspace | Name of table workspace containing a list of reflections. | |
| StartX | Input | number | 0 | Start X (TOF) to refine diffraction pattern. |
| EndX | Input | number | 0 | End X (TOF) to refine diffraction pattern. |
| FunctionOption | Input | string | Refine | Options of functionality. Allowed values: [‘Setup’, ‘Refine’, ‘Save’, ‘Load’] |
| RefinementOption | Input | string | Random Walk | Options of algorithm to refine. Allowed values: [‘Random Walk’] |
| ParametersToRefine | Input | str list | List of parameters to refine. | |
| NumRefineCycles | Input | number | 1 | Number of refinement cycles. |
| ProfileType | Input | string | Type of peak profile function. Allowed values: [‘’, ‘Neutron Back-to-back exponential convoluted with pseudo-voigt’, ‘Thermal neutron Back-to-back exponential convoluted with pseudo-voigt’] | |
| BackgroundType | Input | string | Type of background function. Allowed values: [‘’, ‘Polynomial’, ‘Chebyshev’, ‘FullprofPolynomial’] | |
| FromStep | Input | number | -1 | If non-negative, the previous code is not set from last step, but the step specified. |
| OutputProjectFilename | Input | string | Name of sequential project file. Allowed extensions: [‘.nxs’] | |
| InputProjectFilename | Input | string | Name of sequential project file. Allowed extensions: [‘.nxs’] | |
| ProjectID | Input | string | Project ID. |
The purpose of this algorithm is to provide users a tool to control the workflow to refine powder diffractometer’s peak profile. For Time-Of-Flight powder diffractometers in SNS, back-to-back exponential convoluted with pseudo-voigt profile functions are used. The function is complicated with strong correlated parameters. Thus, the refinement on these parameters contains multiple steps, within each of which only a subset of profile parameters are refined.
In order to control the workflow, there are four major functions supported by this algorithm
* ``Setup`` : set up a few workspaces that will be used to refine profile parameters in multiple steps;* ``Refine`` : select a subset of peak parameters and do Le Bail fit on them;* ``Save`` : save the current refinement status and refinement history to a project file;* ``Load`` : set up a few workspaces used for refining by loading them from a previously created project file. * InputWorkspace : data workspace containing the diffraction pattern to refine profile parameters with;* SeqControlInfoWorkspace : table workspace used to track refinement; Below is the introduction on the fields/columns of this workspace. * "Step" : refinement step. User can start a refinement from the result of any previous ``Step``; * "OutProfile" : name of the table workspace containing refined profile parameters; * "OutReflection": name of the table workspace containing Bragg peaks' peak parameters calculated from refined parameters' value; * "OutBackgroud": name of the table workspace containing the output background parameters' value; * "OutBckgroundParam": name of the output background parameters; * "Refine": profile parameters that are refined in this step; * "RwpOut": output Rwp from refinement; * "LastStep": last step where this step is based on; * "RwpIn": input Rwp * "InProfile": input profile parameter workspace's name; * "InReflection": input Bragg peak parameters workspace' name; * "InBackgroud": input background workspace; * "InBckgroundParam": input background parameters. * InputProfileWorkspace : table workspace contraining starting values of profile parameters;* InputBraggPeaksWorkspace : table workspace containing the Bragg peaks' information for Le Bail fit;* InputBackgroundParameterWorkspace : table workspace containing the background parameters' value* Neutron Back-to-back exponential convoluted with pseudo-voigt : Fullprof profile 9 and GSAS TOF profile 3;* Thermal neutron Back-to-back exponential convoluted with pseudo-voigt: Fullprof profile 10 (a.k.a. Jason Hodges function). * Polynomial* Chebyshev* FullprofPolynomialThis is just a brief description for how to use this algorithm.
1. ``Setup``;2. ``Refine``: refine ``Dtt1`` and ``Zero`` from step 0;3. ``Refine``: reifne ``Alph0`` and ``Beta0`` from step 1;4. ``Refine``: refine ``Alph1`` from step 1 with failure;5. ``Refine``: refine ``Beta1`` from step 1 because step 2 fails; 6. ``Refine``: refine ``Sig-1`` from last step;7. ``Save``: save current work and history to a Nexus file.Categories: Algorithms | Diffraction\Fitting
Python: RefinePowderDiffProfileSeq.py (last modified: 2017-09-06)