CreateMD-v1.rst

.. algorithm::

.. summary::

.. alias::

.. properties::

Description
-----------

This workflow algorithm creates MDWorkspaces in the Q3D, HKL frame using :ref:`algm-ConvertToMD`. 

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 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
#####################

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
#####################################

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.


**Single Conversion Example**
##########################################

.. testcode:: SingleConversion

   # 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
^^^^^^

.. 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
^^^^^^

.. testoutput:: MultiConversion

   [H,0,0]
   [0,K,0]
   [0,0,L]
   DeltaE

.. categories::