Known Bugs in McStas

Previous problems in McStas

Bugs (fixed) in McStas v1.4

These are bugs for which no fix has been released yet, but that will hopefully be fixed in the next release:

The Single_crystal component has a bug that prevents the use of multiple instances of this component in a single instrument. An updated component (v 1.17) is available and will be included in the next release. Thanks to Adrian Hillier for reporting this problem.
The Monitor_nD component has a few bugs when used multiple times in an instrument. An updated component (v 0.13.3) is available and will be included in the next release.
When the value of a component parameter is given as a C variable (as opposed to a constant number or string), a name conflict may happen if the component uses a variable of the same name internally. A workaround is to rename the variable to something not used in the component.
McStas does not give a meaningful error message when there is an inconsistency between the name of a component and the name of the file it is defined in.
When an instrument definition contains an unterminated comment, the resulting error message can be misleading.

These are bugs that have been fixed in McStas v1.3. Upgrade to that or a newer version if you experience any of these.

There is a bug in the Mosaic_simple and Mosaic_anisotropic components. This causes bad statistics and too-high reflectivities for large scattering angles (2theta greater than around 120 degrees). New versions of Mosaic_simple and Mosaic_anisotropic are available and will be included in the next release. Thanks to Miguel A. Gonzalez for reporting this bug.

These are bugs that have been fixed in McStas v1.2. Upgrade to that or a newer version if you experience any of these.

The monochromator component Monochromator.comp does not work with neutrons with wavelength so long that bragg scattering is not possible. A corrected version of the component is available and will be included in the next release.
In the mcplot program, zooming on a plot sometimes selects the wrong plot. Fixed versions of the files mcplot.pl and mcplotlib.pl are available, and will be included in the next release.

These are bugs that have been fixed in McStas v1.1. Upgrade to that or a newer version if you experience any of these.

In the TOF_monitor component, a neutron with a time-of-flight beyond the detector limit may cause another program variable to be corrupted, possibly producing wrong results for the simulation. An updated TOF_monitor component with the bug fixed is now available and will be included in the next version.
McStas does not give a meaningful error message when an instrument definition uses the same name for two components.

These are bugs that were fixed in the McStas v1.01 BETA 1 release.

The Moderator component emits with a distribution that is flat in velocity rather than energy.
[Win32 compatibility] Backslashes in filenames were not correctly quoted in strings in the output C code.
[Win32 compatibility] Instruments with zero parameters failed in a malloc(0) call.

Last modified February 9, 2001 by Per-Olof Åstrand

Last Modified: Tuesday, 22-Jun-2004 14:04:10 CEST