McXtrace - Monte Carlo Xray Tracing, is a joint venture by

Our code is based on technology from

Code repository (shared with 'McStas') is located at github.com/mccode-dev

For information on our progress, please subscribe to our user mailinglist..

To download the latest release: download area
For installation instructions :

McXtrace 3.x installation

For a quick list of the available commands: commands

Recent McXtrace News

Migrating from McXtrace 1.x to 3.x? - Use the wiki-based guides

April 29th, 2025: McStas and McXtrace 3.5.27 released

Dear all,
McStas and McXtrace release 3.5.27 is now available.
McXtrace installation instructions are found on GitHub .

What's Changed - common McStas/McXtrace highlights:

[Feature] McStas and McXtrace are now fully on conda-forge also for Windows, since MCPL 2.0 arrived.
This means that we now recommend to install via this mechanism on Windows. See the instructions for details.
[Feature] mcrun/mxrun have a new -y switch which runs a given instrument using its default parameters.
[BUGFIX] mcplot/mxplot should now deal better with negative / very small numbers in 'log' mode plotting.
[Feature] mcgui/mxgui improved tooltips on the run dialogue.
[Feature] rootmccode works with newer versions of ROOT
[BUGFIX] The KISS random number generator was earlier running with systematically different random numbers (and a shorter period) on Windows.
Identical instruments now run with identical random numbers across platforms, when using identical seed.
[CI, packaging, platform support] Lots of work behind the scenes for portability, packaging, and improved CI of the code on GitHub.
Better standard solutions and easier possibility of spotting when/if we make errors!

What's Changed - McXtrace specific highlights:

[Feature] New components for Fluorescence + Single_crystal and Fluoresence + Powder.
Come with corresponding new test instruments.

What's Changed - McStas specific highlights:

[BUGFIX] As reported on mcstas-users, reflective/transmissive polarisers/analysers could sometimes lead to |P|>1.
This is now fixed by ellimination of "non-up-down" polarisation components when measuring an "up-down" polarisation.
[Feature] Contributed component Source_custom by @pablogila, useful features for simulatiung e.g. CANS and other pulsed sources.
Comes with corresponding new test instrument.

For a full list of changes, please consult the CHANGES or GitHub release notes

April 6th, 2025: Component doc pages back online

We are now in the air with new server hardware.

Among other things this means that component mxdoc pages are back online - by popular demand!

April 5th, 2025: Ongoing webserver upgrade

We are in the process of upgrading the webserver for McStas, McXtrace and other sites. Please bear with us if you experience service interruptions. :-)

February 19th, 2025: McStas and McXtrace 3.5.24 released

Dear all,
McStas and McXtrace release 3.5.24 is now available - McXtrace installation instructons on GitHub .

What's Changed

Important note

McStas and McXtrace will soon change organisation-name on GitHub - from McStasMcXtrace -> mccode-dev

User interfaces and tools

[Feature] mcgui/mxgui Let configuration dialogue spawn your EDITOR to edit your local mccode_config.json by @willend in https://github.com/mccode-dev/McCode/pull/1838 (available also by --edit-user-config from mcrun/mxrun)
[Feature] mcrun/mxrun: New switch --cogen to allow on-demand switch to non-standard code generator. See also interoperability with mccode-antlr below by @willend in https://github.com/mccode-dev/McCode/pull/1851
[Feature] mcrun/mxrun Solution for picking up code generator from PATH if not found where expected by @willend in https://github.com/mccode-dev/McCode/pull/1840
[Feature] pygen minor revision: Build importable make() function and call from generic notebook by @willend in https://github.com/mccode-dev/McCode/pull/1827
[Fix] Support Scintilla editor on Debian with Qt6 by @willend in https://github.com/mccode-dev/McCode/pull/1813
[Fix] Drop hard-coded check for PyQt5 by @willend in https://github.com/mccode-dev/McCode/pull/1814
[Fix] No more hidden Perl dependencies! (perl -> python 1-liner readlinkf()) by @willend in https://github.com/mccode-dev/McCode/pull/1824
[Fix] too-restrictive mcdisplay/mxdisplay instrument line parsing by @g5t in https://github.com/mccode-dev/McCode/pull/1834
[Fix] Patches for mcdisplay/mxdisplay in Windows from @LelandWH https://github.com/mccode-dev/McCode/issues/1853

Components and instruments

[Fix] McStas Vertical_bender: Add max iteration criterion for while loop (default 1000). by @willend in https://github.com/mccode-dev/McCode/pull/1815
[Fix] McStas NCrystal_sample: Remove possible out-of-bounds memory access by @g5t in https://github.com/mccode-dev/McCode/pull/1821
[Fix] McStas Elliptic_guide_gravity and Pol_mirror: Minor comp revisions, suppresses compilation warnings from clang by @willend in https://github.com/mccode-dev/McCode/pull/1826
[Fix] McStas SNS_ARCS.instr edits by @willend in https://github.com/mccode-dev/McCode/pull/1838
[Fix] McStas ISIS_IMAT.instr DEPENDENCY " @NEXUSFLAGS@ " added by @willend in https://github.com/mccode-dev/McCode/pull/1839
[Fix] McStas Union_master Adjustment of default parameter by @willend in https://github.com/mccode-dev/McCode/pull/1840
[Fix] McStas Union-related fixes and imports from DMSC school by @willend in https://github.com/mccode-dev/McCode/pull/1841
[Fix] McStas Elliptical_guide_gravity did not work in GROUPS as it always SCATTERS by @mads-bertelsen in https://github.com/mccode-dev/McCode/pull/1843
[Fix] Monitor_nD on GPU: Adjustments for coherence between CPU and GPU particle lists by @willend in https://github.com/mccode-dev/McCode/pull/1816

Core simulation toolkit

[Feature] NeXus: sort comp instances by index and include comp parameter information by @willend in https://github.com/mccode-dev/McCode/pull/1828
[Fix] Increased stability in NeXus x wide MPI by @willend in https://github.com/mccode-dev/McCode/pull/1811
[Fix] Portability, Windows + cl.exe: Remove variable length array allocations for issue #1817 by @g5t in https://github.com/mccode-dev/McCode/pull/1819 and https://github.com/mccode-dev/McCode/issues/1818 by @willend in https://github.com/mccode-dev/McCode/pull/1822

Interfaces and interoperability with other codes

NCrystal

Thanks to @tkittel for ping-pong on this :)
[Feature] McStas 3.5.24 and later now depends on NCrystal 4.0.0 and later. NCrystal is now available also on Windows! by @willend in https://github.com/mccode-dev/McCode/pull/1848 and https://github.com/mccode-dev/McCode/pull/1855

`mccode-antlr`

Thanks to @g5t for ping-pong on this :)
[Feature] mccode-antlr is an alternative code-generator for McStas and McXtrace - a new development by @g5t and based on ANTLR instead of lex/yacc. The new tool is mainly written in python and thus has a lower barrier for changes in language syntax and code generation. The tool implementations mcstas-antlr and mcxtrace-antlr are thus a candidate implementations to potentially replace the classic mcstas and mcxtrace code generators in the future. Current status is that
- McStas: mcstas-antlr is fully feature complete wrt. mcstas for CPU simulations and close to complete for GPU simulations
- McXtrace: Not all instruments will compile using mcxtrace-antlr but basic functionality is in place
- To try:
  1. Install mccode-antlr from conda-forge or via pip
  2. Adapt your configuration to use e.g. mcstas-antlr by
    - Setting the new --cogen=mcstas-antlr option in mcrun
    - Enable or edit the MCCOGEN field of mccode_config.json using the new Save/Edit configuration in mcgui
    - (The antlr tools default to download comps etc. to an internal cache: Add e.g. -I${MCSTAS} to prefer ingredients fromyour local library)
  3. Use the mcrun-antlr/mxrun-antlr tools provided directly by mccode-antlr

Platform support

Debian/Ubuntu
- [Fix] Make hidden numpy dependency explicit also on Debian by @willend in https://github.com/mccode-dev/McCode/pull/1825
- [Fix] McXtrace meta-pkgs for Debian add libgsl-dev as dependency by @farhi in https://github.com/mccode-dev/McCode/pull/185
Windows
- [Feature] NCrystal is now available with McStas on Windows
- [Info] Windows via cross-compiled .exeinstaller from mccode.org: Please place the MCPL-related .bat files from the extras folder in e.g. c:\mcstas-3.5.24\bin to enable MCPL (May require giving your user 'full access' permissions to the bin folder)
- [Info] Windows via conda-forge: MCPL is not yet available but expected during the spring