LineViewer: empty output in some circumstances

[Janik Zikovsky]

• Create a 3D MDWorkspace with OneStepMDEW(cncs_7860_event.nxs).
• Open in the slice viewer.
• Make a line in the default dimensions (X=Q_lab_X, Y=Q_lab_y).
  • This works
• Swap X and y (X=Q_lab_y, Y=Q_lab_x).
• Make the same line.
  • The line is empty event if it should not be.
  • This is true for BinMD and SliceMD output.

The problem might be in the coordinate transformation, or in the inputs to the algorithms. Only for non-axis aligned binning.

LoadEventNexus(Filename=r'/home/janik/Code/Mantid/Test/AutoTestData/CNCS_7860_event.nxs',OutputWorkspace='md_nxs')
ConvertToDiffractionMDWorkspace(InputWorkspace='md_nxs',OutputWorkspace='md',LorentzCorrection='1')

# This works
SliceMD('md', AxisAligned='0',BasisVectorX='X,units,1,0,0, 0.2,100',
	BasisVectorY='Y,units,0,1,0, 0.2,1',BasisVectorZ='Z,units,-0,0,1, 0.2,1',Origin='-0.1,-0.1,-0.1',OutputWorkspace='md_line1')
# This returns empty
SliceMD('md', AxisAligned='0',BasisVectorX='X,units,1,0,0,0.2,100',
	BasisVectorY='Y,units,0,-1,0, 0.2,1',BasisVectorZ='Z,units,-0,0,1, 0.2,1',Origin='-0.1,0.1,-0.1',OutputWorkspace='md_line2')

[Janik Zikovsky]

Refs #4026: Fixing incorrect ImplicitFunction for Left-handed coordinates

... in SlicingAlgorithm (BinMD, SliceMD) given arbitrary basis vectors. Specifically for the 3D-3D binning case.

commit 8c0ea3e39a5f9b07346d1e1d195e0cc3aad4731d

[Owen Arnold]

Line seems to plot as expected after running through the scenario given in the ticket description.

[Stuart Campbell]

This ticket has been transferred to github issue ​5053