SANSFitShiftScale dialog.
Table of Contents
Fits the high angle workspace and to the low angle bank workspace and provides the required shift and scale
| Name | Direction | Type | Default | Description |
|---|---|---|---|---|
| HABWorkspace | Input | MatrixWorkspace | Mandatory | High angle bank workspace in Q |
| LABWorkspace | Input | MatrixWorkspace | Mandatory | Low angle bank workspace in Q |
| Mode | Input | string | None | What to fit. Free parameter(s). Allowed values: [‘Both’, ‘None’, ‘ShiftOnly’, ‘ScaleOnly’] |
| ScaleFactor | Input | number | Optional | Optional scaling factor |
| ShiftFactor | Input | number | Optional | Optional shift factor |
| OutScaleFactor | Output | number | Applied scale factor | |
| OutShiftFactor | Output | number | Applied shift factor |
This algorithm is used to fit data from the high-angle bank to data from the low-angle bank in a SANS experiment. The degrees of freedom are a shift and a scale factor which determine by how much the high-angle bank data needs to be scaled and then shifted to match the low-angle bank data.
There are 4 available fit modes used to scale and shift the high angle bank data so that it matches up with the low angle bank data. Where fitting is required Fit v1 is used with a composite function comprised of a FlatBackground and TabulatedFunction. In all cases the shift and scale are used to alter the counts and errors for the high angle bank.
None is the mode for no fit determined scaling or shifting. In this case the ScaleFactor and ShiftFactor properties must both be provided. With Both, fitting is used to establish optimum parameters for both the scaling and shifting of the high angle bank data. ScaleOnly mode ties the shift, so ShiftFactor must be provided. ShiftOnly mode ties the scale so ScaleFactor must be provided.
Example - Simple shift:
hab_ws= CreateWorkspace(DataX=range(4,10), DataY=[1]*5, UnitX='MomentumTransfer')
lab_ws = CreateWorkspace(DataX=range(0,6), DataY=[6]*5, UnitX='MomentumTransfer')
uniform_binning = [0, 1, 10]
hab_ws= Rebin(hab_ws, Params=uniform_binning)
lab_ws = Rebin(lab_ws, Params=uniform_binning)
scale, shift = SANSFitShiftScale(HABWorkspace = hab_ws, LABWorkspace =lab_ws, Mode='ShiftOnly', ScaleFactor=1.0)
print scale
print shift
Output:
1.0
2.5
Categories: Algorithms | SANS
Python: SANSFitShiftScale.py