name: DIALS core meeting 2021-02-11
tags: core meeting
# DIALS core meeting 2021-02-11
## Previous Actions
* [ ] MG+ND: write a proposal for ['overall architecture discussion'](https://dials.github.io/kb/core/20200903#overall-architecture-discussion) and ['new installer'](https://dials.github.io/kb/core/20200903#new-installer)
* [ ] MG+ND: Come up with a proposal to [move away from all code being in header files](https://dials.github.io/kb/core/20201001#overall-architecture-discussion) and consolidate into a single library
* Will discuss new installer on the 23rd at 10:00
* [ ] MG: organise a [typing intro lecture](https://dials.github.io/kb/core/20200917#typing-mypy), likely to happen in Q2.
* [ ] [cbflib conda-forge package](https://dials.github.io/kb/core/20201125#cbflib-conda-forge-package)
* [ ] ND to prepare an agenda for the HDRMX meeting in March
* [ ] ASB to organise a side-meeting next to the HDRMX workshop
* [ ] ASB to explore what should happen to cbflib maintenance in the future
* [ ] ND to set up a [`cbflib_adaptbx` pull request](https://dials.github.io/kb/core/20201125#cbflib_adaptbx-dependency) for MAR detector fixes. Verify with `labelit_regression`.
* [x] [ASB to review](https://dials.github.io/kb/core/20210128#per-image-analysis-related-prs) [dxtbx#289](https://github.com/cctbx/dxtbx/pull/289)
* [ ] ASB [to run tests on dxtbx#288 as per comment](https://github.com/cctbx/dxtbx/pull/288#issuecomment-769206024)
* [x] MG to send an email to dials-support on how to avoid `UserWarning`
* [ ] [PR dials#1567](https://github.com/dials/dials/pull/1567)
* [x] ASB to [add xfel test instructions](https://dials.github.io/kb/core/20210128#drop-python-2-idioms-and-compatibility-fixes-dials1567) to the PR
* [ ] Then GW to [run tests and merge](https://dials.github.io/kb/core/20210128#drop-python-2-idioms-and-compatibility-fixes-dials1567) if passing
* [ ] [dx2 proposal](https://dials.github.io/kb/core/20210128#dx2-proposal)
* [x] ASB to reply on list
* [ ] ~~GW to merge all the different discussion strains together~~
* [ ] MG to put in a PR to dx2 turning the readme to a proposal
### Construct Experiments directly rather than via DataBlocks [#288](https://github.com/cctbx/dxtbx/pull/288)
(already has a merge conflict)
This was discussed in the open action points above.
### `dials.index`: create new experiments
`dials.index` should (or should not) create new experiments with crystals in rather than modifying in place existing experiments [as proposed in this issue (#1029)](https://github.com/dials/dials/issues/1029)
* Q: This would double the size of serial experiments?
* A: It wouldn't double the size, but increase the size slightly, and there are more pointers.
* The impact of this could be tested before work on this is done.
ASB ran this test during the meeting and added results to the ticket.
Results look favourable.
* Q: Is there any further objection to this if the performance impact isn't a blocked?
* A: No obvious objections. This could lead to downstream work needed to clean up afterwards.
Change in behaviour would only affect `dials.index` command line program, not the API call (thus not stills processing).
If `dials.index` gets a single experiment and can't find a lattice - should it write out the input file as is -- ie. not add a lattice, not reassign experiments, [#1080](https://github.com/dials/dials/issues/1080)? Sentiment is that it should definitely still terminate with a non-zero exitcode for scripting purposes. Writing out the input file means users may pass the file on to `dials.refine` and get hit with an even less informative error message.
### Renaming `master` → `main`
[xia2](https://github.com/xia2/xia2/) has now renamed its main branch. Plan is to do the same with DIALS and dxtbx in <2 weeks time.
### Next meeting
Thursday, February 25th, 4pm UK time, 8am PDT.