Telco 20230419

Date

Wednesday, 19th April, 15:00 UTC

Connect

• ZOOM VC link: https://hu-berlin.zoom.us/j/65272091306?pwd=WUxEa0ZtVXp1ZHlsSlVjU2lmclMrQT09
• Meeting ID: 652 7209 1306
• Passcode: nexus

Agenda

• CodeCamp
• issues

Present

SB, AB, CP, HM, RO, DMcR, MK, PM, PJ, RB, TC, WdN, BB, BW, HG, CZ, TM, and Matthew Newille(APS)

Minutes

• Codecamp Agreed period: June 15-16 & 20-21, 2023

• XAS.  From Ray: “Your concerns do however suggest that we need to find a way to identify which category best describes a particular application definition, perhaps by providing some provenance information or defining a maintainer. I can only attend the first half hour tomorrow, but I believe this is something well worth discussing.” https://github.com/nexusformat/definitions/issues/1011
  • BW: XAS experiments are also using https://manual.nexusformat.org/classes/applications/NXstxm.html#nxstxm, but NXxas is not in a good shape
  • HG/PM: EXAFS would also be happy to build on top of NXxas
  • BW: flexible sample and detection systems are required,although the main structure is always similar
  • MN: EXAFS standards and dataformats exist on top of hdf5. NeXus is pushed but proper support is still needed.
  • RO: NX started with instrument and data collection description, but then AppDef arrived to define interface between data producer and consumer.
  • MN: EXAFS would need clear common definitions, like monochromator d spacing, etc. RAW data is nice to have, but calibrated is even more important. What can be stored in Nexus
  • SB: both, it depends on the community. See analogy with NXmonopd.
  • BW: we can use immediately base classes e.g. NXdetector
  • RO: multiple AppDef can de satisfied by a single file or an AppDef and other base classes
  • MN: What kind of definitions are supplied by NeXus?
  • BW: NXdetector is already for multi-dim detectors, and can be used (if needed also extended) Ideas can be taken from NXstxm.
  • AB: You can propose new definitions so we can review and vote on it.
  • RO: we could define maintainers for all AppDefs
  • AB: Great! Main (NIAC) contacts can be added to the
  • MN: maybe IUcR representative?
  • PJ: technical contacts and follow how much the community is using the definitions.
  • PM: also data analysis developers could be in the loop.
  • AB: deprecation should be done VERY carefully.
  • RO: APS and FAIR requirements with NeXus
  • BW: what is the timeline for XAS?
  • MN: do it right rather than quick.
• Get status on NXdata: improve documentation regarding axes https://github.com/nexusformat/definitions/pull/1213
  • WdN: AXISNAME_INDICES - is it a scalar or an array?
  • WdN: AXISNAME - what is its dimension should be? Is it 1D array or not?
  • RO: how to plot it?
  • WdN: ESRF implemented it with matplotlib
  • SB: use xarrays https://docs.xarray.dev/en/stable/examples/multidimensional-coords.html
  • TC: non-regular gidding shall be supported.
  • BW: recording must be supported. visualisation is secondary.
    NXdata: data vs.plot?! (RO: data, but with a sensible look on it)
  • PJ: NXcanSAS: use of multi-dimensional axis array (e.g. at Diamond I22)
  • RO: make a session on the code-camp
  • AB: the PR could have a py plotting code included

May Telco

Please help to choose the date by responding to the poll by April 30. We are planning to hold the telco in the regular slot of UTC 15:00. Check your local time to avoid scheduling surprises!