SaveNexusProcessed/LoadNexusProcessed round trip bug

[Raquel Alvarez Banos]

Run the following script to reproduce the issue:

X = [0,1,2,3,4,5] + [0,10,20,30,40,50] + [0,100,200,300,400,500]
Y = [0,1,2,3,4,5] + [0,10,20,30,40,50] + [0,100,200,300,400,500]
ws = CreateWorkspace(DataX=X,DataY=Y,NSpec=3)

SaveNexusProcessed(InputWorkspace=ws,Filename='test.nxs')
ows = LoadNexusProcessed(Filename='test.nxs')
print CheckWorkspacesMatch(ws,ows)

ws and ows do not match because ws is a point-like workspace (n x values and n y values) but LoadNexusProcessed is assuming a histogram workspace and loading n+1 x values.

[Raquel Alvarez Banos]

This other script works fine:

X = [0,1,2,3,4,5]+[0, 1, 2, 3, 4, 5]+[0,  1,  2,  3,  4,  5]
Y = [0,1,2,3,4,5]+[0,10,20,30,40,50]+[0,100,200,300,400,500]
ws = CreateWorkspace(DataX=X,DataY=Y,NSpec=3)
SaveNexusProcessed(InputWorkspace=ws,Filename='test.nxs')
ows = LoadNexusProcessed(Filename='test.nxs')
print CheckWorkspacesMatch(ws,ows)

It seems that the problem arises when ws is a point-like workspace and the X values are not shared by all the spectra.

[Raquel Alvarez Banos]

The bug is caused by line 1951 in LoadNexusProcessed.cpp:

  const int64_t nxbins(nchannels + 1);

I think the number of X values should be read from xbins.dim1()

[Raquel Alvarez Banos]

Re #11877 Fix the bug

Changeset: d23c2bbaa8978c7a21cc20da6bd2507a384ed4fd

[Raquel Alvarez Banos]

Re #11877 Add a couple of unit tests

Changeset: dfb8cd9db7b2029cc7e209e108e8b125dc839d8e

[Raquel Alvarez Banos]

Re #11877 Clang format

Changeset: f74859e508c6b86fb433a03fc6e8d0cae2cd9161

[Raquel Alvarez]

This is being verified as ​pull request #832.

[Raquel Alvarez Banos]

(In #5406) Before writing the system test I first need to solve #11877

[Dan Nixon]

The change seems to be fine, I'll run the doctests locally and if they pass there I'll merge it.

[Dan Nixon]

Merge pull request #832 from mantidproject/11877_SaveNexusProcessedLoadNexusProcessed_round_trip

Fix LoadNexusProcessed bug

Full changeset: ​6d19154e9f85cd1a22ec3869e01bf792a8cc828f

[Stuart Campbell]

This ticket has been transferred to github issue ​12715