13.5 Highlights of What’s New in Version 2019.4.0
Here is a summary of what’s changed since release 2019.3.0. Historical change logs are collected in Section
13.5.1 Bug Fixes for Elements
- The ILMATRIX element lacked path-length terms related to the betatron amplitude, and also
did not properly handle non-zero αx,y and ηx,y′, as pointed out by forum user Teresia.
- A bug was fixed in back-tracking for SBEN elements with nonzero values for HGAP and FINT.
This was reported by Y. Park (UCLA).
13.5.2 Bug Fixes for Commands
- The bunched_beam command was not
generating particle ID values when use_moments_output_values=1, as reported by Z. Duan
13.5.3 New and Modified Elements
- Added SPARSE_INTERVAL parameter to the WATCH element, to allow sparsing coordinate
output with regular spacing. This supplements the FRACTION parameter, which provides
random sampling, and the START_PID and END_PID parameters, which provide sampling of a
subset defined by particle ID.
- Added RPN_PARAMETERS parameter to the SCRIPT element, which directs the program to load
SDDS parameter values from the script output file into rpn variables, where they may be
used for optimization. This provides the user the ability to perform script-based analysis of
particle distributions and then optimize the results of that analysis.
- The N_BINS parameter of the WAKE and TRWAKE elements now defaults to zero, which prevents
some undesirable behavior when warnings are overlooked. This was requested by R. Lindberg
- The EDRIFT, EHVCOR, EHCOR, EVCOR, CSBEND, KQUAD, KSEXT, KOCT, and UKICKMAP elements can
now be used with back-tracking (see run_setup).
13.5.4 New and Modified Commands
- The chaos_map command is now available. As the name suggests, it is similar to a frequency
map, but provides other measures of chaotic motion. This includes a promising new approach
outlined by Y. Li et al. .
- The optimization_variable command has a new parameter differential_limits, which
permits specifying that the lower and upper limits are being given relative to the initial value,
rather than in absolute terms.
- The tune_footprint command has a new parameter separate_xy_for_delta, which
permits specifying that tracking for the x and y momentum-dependent tunes should be done
either in a combined fashion (default) or separately. The latter might be helpful if nonlinear
coupling of y motion into the x plane causes the x tune to be poorly determined for small x
- Added egaussian mode to the ion_effects command. This mode results in computation of
the fields from the electrons assuming a gaussian distribution, as normal, but determines the
kick to the ions based purely on momentum conservation. This was inspired by the work of
M. Blasciewicz (BNL) and implemented with J. Calvey (ANL).
- Added multiple_ionization_energy_peak
and multiple_ionization_energy_rms parameters to the ion_effects command, allowing
control of the peak and rms energy of ions produced by multiple ionization. This was done
by J. Calvey (ANL).
13.5.5 Changes Specific to the MPI Parallel Version
13.5.6 Changes Specific to the GPU Version
The GPU version continues to be an alpha release and contains bugs. Users are
encouraged to check results against the serial or parallel versions and report issues to the
13.5.7 Changes to Related Programs and Files