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Nick Draper authored
Upper case causes it not to work re #22143
Nick Draper authoredUpper case causes it not to work re #22143
Description
This workflow algorithm creates MDWorkspaces in the Q3D, HKL frame using :ref:`algm-ConvertToMD`.
Using the FileBackEnd and Filename properties the algorithm can produce a file-backed workspace. Note that this will significantly increase the execution time of the algorithm.
Setting the UB matrix
u and v are required. u and v are both 3-element vectors. These specify how the crystal's axes were oriented relative to the spectrometer in the setup for which you define psi to be zero. u specifies the lattice vector that is parallel to the incident neutron beam, whilst v is a vector perpendicular to this in the horizontal plane. In :ref:`UB matrix <Lattice>` notation, u and v provide the U matrix. See :ref:`algm-SetUB`. Alatt and Angdeg are the lattice parameters in Angstroms and lattice angles in degrees respectively. Both are 3-element vectors. These form the B-matrix.
Goniometer Settings
If goniometer settings have been provided then these will be applied to the input workspace(s). For multiple input workspaces, you will need to provide goniometer settings (Psi, Gl, Gs) as vectors where each element of the vector corresponds to the workspace in the order listed in InputWorkspaces. You do not need to provide the goniometer settings at all. If you run :ref:`algm-SetGoniometer` individually on the input workspace prior to running CreateMD, then those settings will not be overwritten by CreateMD.
EFix
The EFix value may be provided for input workspaces. Specifying a single value, will ensure that that value is applied to all input DataSources. EFix can also be provided as an array provided that the array is the same length as the DeataSources, in this case, the EFix values will be matched to the DataSources based on index. EFix has units of meV.
Merging Individually Converted Runs
If a sequence of input workspaces are provided, and InPlace is False, then these are individually processed as above, and are merged together via :ref:`algm-MergeMD`. Intermediate workspaces are not kept. If InPlace is applied conversion and merging are done in the same step. This requires less memory overhead, however input workspaces are altered.
Additional Information
CreateMD steps use :ref:`algm-ConvertToMDMinMaxGlobal` to determine the min and max possible extents prior to running :ref:`algm-ConvertToMD` on each run.

Horace style orientation used by CreateMD. DSPI and Omega in the image have no meaning in Mantid and are not required by this algorithm.
Workflow
Conversion Of Multiple Input Files Example
import numpy as np
# Create arrays of run numbers and corresponding values of psi
run_numbers = range(15052, 15098)
psi_array = np.arange(0.0, 92.0, 2)
# Create list of file names from run numbers
input_runs = ['/path/to/data/instr_'+str(run_number)+'.nxspe' for run_number in run_numbers]
md_ws = CreateMD(input_runs, Emode='Direct', Alatt=[2.87, 2.87, 2.87], Angdeg=[90, 90, 90], u=[1, 0, 0,], v=[0, 1, 0], Psi=psi_array, EFix=400.0)
Conversion Of A Single Input Workspace Example
# Create some input data.
current_ws = CreateSimulationWorkspace(Instrument='MAR', BinParams=[-3,1,3], UnitX='DeltaE')
AddSampleLog(Workspace=current_ws,LogName='Ei',LogText='3.0',LogType='Number')
# Execute CreateMD
new_mdew = CreateMD(current_ws, Emode='Direct', Alatt=[1.4165, 1.4165,1.4165], Angdeg=[90, 90, 90], u=[1, 0, 0,], v=[0,1,0], Psi=6, Gs=0, Gl=[0])
# Show dimensionality and dimension names
ndims = new_mdew.getNumDims()
for i in range(ndims):
dim = new_mdew.getDimension(i)
print(dim.getName())
Output
[H,0,0]
[0,K,0]
[0,0,L]
DeltaE
Conversion Of Multiple Input Workspaces Example
# Create multiple runs
input_runs = list()
psi = list()
gs = list()
gl = list()
for i in range(1, 5):
current_ws = CreateSimulationWorkspace(Instrument='MAR', BinParams=[-3,1,3], UnitX='DeltaE', OutputWorkspace='input_ws_' + str(i))
input_runs.append(current_ws.name())
psi.append(float(5 * i))
gl.append(0.0)
gs.append(0.0)
# Convert and merge
new_merged = CreateMD(input_runs, Emode='Direct', Alatt=[1.4165, 1.4165,1.4165], Angdeg=[ 90, 90, 90], u=[1, 0, 0,], v=[0,1,0], Psi=psi, Gl=gl, Gs=gs, EFix=3.0)
# Show dimensionality and dimension names
ndims = new_merged.getNumDims()
for i in range(ndims):
dim = new_merged.getDimension(i)
print(dim.getName())
Output
[H,0,0]
[0,K,0]
[0,0,L]
DeltaE
Multi Conversion Example Without Altering Original Workspaces (InPlace=False)
# Create multiple runs
input_runs = list()
psi = list()
gs = list()
gl = list()
for i in range(1, 5):
current_ws = CreateSimulationWorkspace(Instrument='MAR', BinParams=[-3,1,3], UnitX='DeltaE', OutputWorkspace='input_ws_' + str(i))
input_runs.append(current_ws.name())
psi.append(float(5 * i))
gl.append(0.0)
gs.append(0.0)
# Convert and merge. ConversionToMD done in place.
new_merged = CreateMD(input_runs, Emode='Direct', Alatt=[1.4165, 1.4165,1.4165], Angdeg=[ 90, 90, 90], u=[1, 0, 0,], v=[0,1,0], Psi=psi, Gl=gl, Gs=gs, EFix=3.0, InPlace=False)
# Show dimensionality and dimension names
ndims = new_merged.getNumDims()
for i in range(ndims):
dim = new_merged.getDimension(i)
print(dim.getName())
Output
[H,0,0]
[0,K,0]
[0,0,L]
DeltaE