TransformMD v1#
Summary#
Scale and/or offset the coordinates of a MDWorkspace
See Also#
Properties#
Name |
Direction |
Type |
Default |
Description |
|---|---|---|---|---|
InputWorkspace |
Input |
IMDWorkspace |
Mandatory |
Any input MDWorkspace. |
Scaling |
Input |
dbl list |
1 |
Scaling value multiplying each coordinate. Default 1. Either a single value or a list for each dimension. |
Offset |
Input |
dbl list |
0 |
Offset value to add to each coordinate. Default 0. Either a single value or a list for each dimension. |
OutputWorkspace |
Output |
IMDWorkspace |
Mandatory |
Name of the output MDWorkspace. |
Description#
This algorithm applies a simple linear transformation to a MDWorkspace or MDHistoWorkspace. This could be used, for example, to scale the Energy dimension to different units.
Each coordinate is transformed so that \(x'_d = (x_d * s_d) + o_d\) where:
d : index of the dimension, from 0 to the number of dimensions
s : value of the Scaling parameter
o : value of the Offset parameter.
You can specify either a single value for Scaling and Offset, in which case the same m_scaling or m_offset are applied to each dimension; or you can specify a list with one entry for each dimension.
Notes#
The relationship between the workspace and the original MDWorkspace, for example when the MDHistoWorkspace is the result of BinMD v1, is lost. This means that you cannot re-bin a transformed MDHistoWorkspace.
No units are not modified by this algorithm.
Performance Notes#
Performing the operation in-place (input=output) is always faster because the first step of the algorithm if NOT in-place is to clone the original workspace.
For MDHistoWorkspaces done in-place, TransformMD is very quick (no data is modified, just the coordinates).
For MDWorkspaces, every event’s coordinates gets modified, so this may take a while for large workspaces.
For file-backed MDWorkspaces, you will find much better performance if you perform the change in-place (input=output), because the data gets written out to disk twice otherwise.
Categories: AlgorithmIndex | MDAlgorithms\Transforms
Source#
C++ header: TransformMD.h
C++ source: TransformMD.cpp