McStas/McXtrace v3.7.1

Changes in McStas/McXtrace 3.7.1, May 21st, 2026

What's Changed

Main new developments:

Common McStas and McXtrace developments:

• Up to 10 USERVARS supported with Monitor_nD (named user0,...,user9)
• Qt5 → Qt6 across the package and dependencies
• Bugfix: Fix of rare visualisation bug in mcdisplay/mxdisplay (e.g. box was not allowed as a comp name)
• Doc improvements:
  • mcdoc/mxdoc can render .tex and .md in addition to .html
  • Example instruments come with an in-repo README.md generated via this mechanism
  • See e.g. McStas BNL_H8 or McXtrace ESRF ID01
• CI/test improvements:
  • mcdisplay/mxdisplay visualisation is performed as part of mctest/mxtestruns (→ CI)
  • See top html files in McStas and McXtrace nightly test runs

McStas specific developments:

• Integrated support for KDSource
  • New component KDSource
  • For usage details, see example instrument Test_KDSource and the KDSource documentation website
  • Available as automatic dependency on conda-forge based installations (including macOS and Windows 'installers'
  • Not available as .deb package on Debian systems but may function by installing via pip.
    Recommendation: Just use conda-forge.
• Pulse-length adjustment available for ESS_butterfly
  • Handled via specifically named instrument input parameter and DEPENDENCY line
  • See example instrument ESS_butterfly_Adjustable_Pulse
• PowderN now supports NCrystal cfg-strings.
  • Forwards request to NCrystal that populates datastructures without intermediate .laz/.lau files
  • See example instrument Test_Powders - comp=0 mode
• Bugfixes:
  • Fix to Union, orientation of loggers wrt. master comp
  • Bugfixes to recently added improved Union mesh
• Contributions from NBI/KU:
  • Inhomogenous_incoherent_process in Union from @Lomholy, (via ‘tinyexpr' string-expression inputs) - see rel. test instrument
  • New spinwave comp SpinWave_BCO from @SSBNS - see rel. test instrument
  • ESS KVASIR instrument proposal - backend instrument with MCPL input from BIFROST optic. @AmalieFalkenberg. Includes Jupyter notebook in McStasScript syntax.
• McStas component manual uses .tex snippets from generated via components mcdoc

McXtrace specific developments:

• Much improved Union subsystem for McXtrace by @ebknudsen. Makes use of Xraylib for Compton and Rayleigh scattering models.
• Test instruments for the new Union processes, both from @ebknudsen
  • PowderCompton_union - Compton scattering and powder diffraction
  • Test_KN_Comp_Rayl_union - test instrument using Klein-Nishina, Rayleigh, or Compton
    scattering processes.

Detailed list - from the git commit log:

• Shift item in changelogs by @willend in #2400
• Minor manual patches by @willend in #2403
• Fixes to AI doc/manual patches by @willend in #2405
• Ensure to fill all BINS-oriented detector struct members by @willend in #2407
• Inhomogenous incoherent process in Union by @Lomholy in #2402
• Remove deprecated NCrystal-oriented workaround by @willend in #2411
• Suppress loading/plotting of event lists by @willend in #2412
• Fixes #2301 - endorse use of sasmodels comps by @willend in #2413
• Fix for #759 by @willend in #2414
• First stab at fixing #2406 by @willend in #2415
• Make basictest workflow structure more similar across conda / non-conda flows. by @willend in #2417
• Follow-up to #2402, should complete #2305 by @willend in #2418
• Disable MPI when testing non-conda mingw Windows by @willend in #2420
• mctest logs: More information in case of failures / numerical discrepancies by @willend in #2422
• Sync mesh_bugs from main CI dev by @Lomholy in #2423
• Fix to mctest issue: A failed test status would be inherited by subsequent tests by @willend in #2425
• Various improvements mctest by @willend in #2427
• Add jinja2 in windows non-conda CI workflows by @willend in #2429
• Expand Monitor_nD to 10 uservars + other work on monitors by @willend in #2428
• Example instrument with adjustable ESS pulse-length. by @willend in #2430
• Follow-up to #2428, required interface changes by @willend in #2431
• Fix annoying typos in newly-arrived instrument by @willend in #2432
• First attempt at making PowderN load NCMAT data directly via NCrystal by @tkittel in #2371
• Disable non-conda Windows CI. Broken in too many ways. We test that platform through conda only. by @willend in #2439
• union system updated for McXtrace 3 by @ebknudsen in #2282
• Fix for #2436 (McStas+McXtrace) and #2406 (McXtrace) by sync by @willend in #2440
• NCrystal sampling now use the correct per-particle RNG stream by @tkittel in #2437
• Follow up xrl union: Ensure better platform independence via @XRLFLAGS@ by @willend in #2441
• KDSource incoming by @willend in #2442
• Clean up KDSource comp/instr docs by @willend in #2443
• KDS in display section by @willend in #2446
• Initial steps toward fixing #2435 by @willend in #2448
• Candidate fix for #2434 by @willend in #2447
• mctest/mcviewtest: Log and present mcdisplay output pr. example instr by @willend in #2449
• CI/Infrastructure: Update conda-based workflows to use conda-incubator/setup-miniconda@v4 by @willend in #2450
• Consequence-edits after #2447, non mccodelib-parser mcdisplay tools by @willend in #2451
• webgl-classic mode works best with pure line-based visualisation by @willend in #2452
• Revert mcdis-prefixes for polygon / polyhedron (had side-effects) by @willend in #2453
• Fixes for failed visualisation of selected instrs in mctest by @willend in #2454
• Add trailing newlines as these lines interfere with mcdisplay/GPU by @willend in #2455
• Drop seed in %Example line by @willend in #2456
• Mesh bugs by @Lomholy in #2424
• Various bits of work for mcdisplay / from mctest and on GPU. by @willend in #2458
• Repair of mcdisplay-backends post PR #2447 (for fix of #2434) by @willend in #2459
• Run KDSource test-instrument also within the MCPL-test section by @willend in #2460
• Small changes to tiny expression for improved usability by @Lomholy in #2463
• New spin wave comp by @SSBNS in #2373
• Union logger transformations by @mads-bertelsen in #2426
• Apply clangformat to SpinWave_BCO.comp by @willend in #2465
• DRAFT prototyping for in-repo .md comp/instr docs by @willend in #2404
• Adding KVASIR secondary spectrometer mcstas script model by @AmalieFalkenberg in #2345
• ESS_KVASIR instrument model cleanup by @willend in #2466
• Import of component work from #2344 by @willend in #2467
• Preparations to fully support PyQt5/PyQt6/PySide via qtpy by @willend in #2468
• Use qtpy and avoid explicit PyQt5 requirement in devel script by @willend in #2469
• Various doc fixes etc toward release 3.7.0 by @willend in #2470
• Partial fix for #2396 by @willend in #2472
• Update for 3.7.0 -> 3.7.1 ... by @willend in #2473

New Contributors

• @SSBNS made their first contribution in #2373
• @AmalieFalkenberg made their first contribution in #2345

Full Changelog: v3.6.14...v3.7.1