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.. algorithm::
.. summary::
.. alias::
.. properties::
Description
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This workflow algorithm creates MDWorkspaces in the Q3D, HKL frame using :ref:`algm-ConvertToMD`.
Setting the UB matrix
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*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 UB matrix 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
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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.
Merging Individually Converted Runs
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If a sequence of input workspaces are provided then these are individually processed as above, and are merged together via :ref:`algm-MergeMD`. Intermediate workspaces are not kept.
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.
.. figure:: /images/HoraceOrientation.png
:alt: HoraceOrientation.png
`Horace <http://horace.isis.rl.ac.uk/Generating_SQW_files>`__ style orientation used by CreateMD. DSPI and Omega in the image have no meaning in Mantid and are not required by this algorithm.
##########################################
# 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()
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.. testoutput:: SingleConversion
[H,0,0]
[0,K,0]
[0,0,L]
DeltaE
**Multi Conversion Example**
##########################################
.. testcode:: MultiConversion
# 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())
AddSampleLog(Workspace=current_ws,LogName='Ei',LogText='3.0',LogType='Number')
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)
# Show dimensionality and dimension names
ndims = new_merged.getNumDims()
for i in range(ndims):
dim = new_merged.getDimension(i)
print dim.getName()
Output
^^^^^^