13.21 Highlights of What’s New in Version 30.0, 5 July 2016
Here is a summary of what’s changed since release 29.1:
13.21.1 Bug Fixes for Elements
- Fixed a memory leak in the FTABLE element.
13.21.2 Bug Fixes for Commands
- Fixed calculations of exact normalized emittance (error in equations) and implemented in
parallel version. This bug impacted results in the sigma output file of the run_setup command
and in WATCH output in parameter mode. J. Bjorklund pointed out the lack of calculations
in the parallel version and provided an example run that helped discover the problem with
the serial version.
- The diffusionRate output from the frequency_map command is now computed as
log 10((Δνx2 + Δνy2)∕n) instead of (log 10(Δνx2 + Δνy2))∕n.
- Fixed a bug in bunched_beam whereby the centroids for a shell-type beam were offset from
zero. Reported by L. Emery (ANL).
- Fixed bug in moments_output when bending magnts with non-zero ETILT are present. When
this occurs, the number of slices for moments calculation is set to 1 for those elements, to
avoid numerical problems with the vertical orbit.
13.21.3 New and Modified Elements
- Added the LEFFECTIVE parameter for QUAD and KQUAD, which provides a convenient way to
change the effective length without changing the adjacent drift spaces. Also added the ability
to turn off the linear fringe field effects while keeping the nonlinear part, and to multiply the
nonlinear effects by a numerical factor.
- Added the BMXYZ element for straightforward integration through 3D field maps for straight
- Added the BRAT element, which is similar to BMXYZ but accommodates curved elements.
Elements may be asymmetric, e.g., longitudinal gradient dipoles.
- Added the FACTOR and THRESHOLD options to FTABLE. The former allows multiplying the fields
by a user-defined factor. The latter allows specifying the magnitude of the field below which
it is considered zero, which can help ensure numerical stability.
- The FTABLE element can accept the simple-to-create input files used by the BMXYZ element in
addition to the original input format.
- Results that depend on the transport matrix will show small changes for elements for which
the matrix is determined by tracking. The tracking-based method was modified to use a larger
number of sample points, increasing the accuracy.
13.21.4 New and Modified Commands
- Added the full_grid_output parameter to the frequency_map command, making it possible
to display frequency maps using sddscontour.
13.21.5 Changes Specific to Parallel Version
- Implemented exact normalized emittance calculations for the sigma output file of the
run_setup command and in WATCH output in parameter mode. J. Bjorklund pointed out the
lack of calculations in the parallel version.
- Fixed bug in assignment of particle ID values when using Halton sequences in the
13.21.6 Changes to Related Programs and Files
- The program abrat (“Asymmetric Bend RAy tracing”) was added. It allows tracking electrons
through 2- and 3-D magnetic field maps. It is a commandline version of the BRAT element.
- The script ionTrapping was added, providing simple ion trapping calculations for uniform
bunch trains. J. Calvey (APS) helped with debugging.
- The script computeSCTuneSpread was added to allow computation of space-charge tune
- The script radiationEnvelope now computes envelopes for central cone flux.