Telco 20170711


Tuesday, 11 July, 16:30 CEST (+0200)

Hangout Link:



Present: MB, MK, PJ, AB, TSR, EW, FA, HJB

Code Camp 2017

Target is last week of October, for about three days, hosted by DLS.

Ongoing Projects

Release 3.3

Looks like it is ready to go. There is an automated script that generates release notes. Mid term they could move into the wiki part of that repo space.

Target date for the next release is January, or maybe earlier at the Code Camp?


All are in agreement that this is a good idea. HJB talks to COMCIFS and COMDATA around the IUCr meeting in August. We can look at the implementation at the code camp.


Nothing to report and on the back burner. DLS suggested dropping from the agenda until some progress is made there.

Identifying data sources in NXdata

DLS have prepared and example and no one could come up with a better proposal. They will put this to the test in practise now.


We clarified the preferences raised in emails and the ticket system with the conclusion that “left” and “right” are unnecessarily vague concepts possibly overloaded with local conventions. Positive/negativ x/y direction is directly tied to the NeXus coordinate systen and will be the choice for the new proposal.


We did not discuss the CSPAD, but aligning timestamped data in NXlogs written with different frequencies using the cue indices.

AB would like to see some full example file. TSR may have one or could create one for one of the next meetings. MB indicated the same. Would be nice to compare.

Ragged arrays

They are more of an HDF5 problem than a NeXus one. There is no simple efficient way to deal with them. Either you end up with many unused chunks and lots of metadata or you need to flatten the dimensions and have a run length index dataset. AB will investigate relative merits with LCLS people.

HDF5 filters repo

Eugen is making progress on simplifying the build system, which is currently too complex to maintain.

Next Meeting

Telco 20170725


Dropped due to lack of time.