13.25 Highlights of What’s New in Version 34.0, 31 October 2017

Here is a summary of what’s changed since release 33.1.1.

13.25.1 Bug Fixes for Elements

• A bug in the IONEFFECTS element was reported by J. Cavley (APS): when only one bunch was present, the electron beam coordinates were zeroed out.
• A bug in the WATCH element caused elegant to crash in centroid and parameter mode when the WATCH element was in a beamline branch that did not get executed on the first pass.
• In multi-step runs, the STEERING_MULTIPOLES input for the EKICK, EHKICK, and EVKICK elements was ignored except on the first step.

13.25.2 Bug Fixes for Commands

• A bug in the ion_effects command was reported by J. Cavley (APS): when only one bunch was present, the electron beam coordinates were zeroed out.
• The center_arrival_time feature of sdds_beam did not work correctly for the parallel version, as reported by Jonas Björklund.
• The use_moments_output_values qualifier of the bunched_beam command did not work for the parallel version.
• The full_grid_output mode of the frequency_map command provided incorrect results for the diffusion for particles that got lost.
• The parameters output file from the run_setup command incorrectly reported the length and angle of CSBEND elements when element division was invoked. This was reported by V. Sajaev (APS).
• The amplification_factors command now respects link_elements commands.
• The tune_footprint command now optionally runs in major action command mode. The inability to do so was pointed out by Y.-P. Sun (APS).

13.25.3 New and Modified Elements

• The long-deprecated DIRECTION parameter of the SCRAPER element has been removed; input files using the SCRAPER element will need to be updated to remove this parameter and replace it with equivalent INSERT_FROM parameter. One result is that the SCRAPER element can now support two-sided scrapers.
• Added the SYSTEMATIC_MULTIPOLE_FACTOR, RANDOM_MULTIPOLE_FACTOR, and STEERING_MULTIPOLE_FACTOR parameters to the KQUAD, KSEXT, and KOCT elements. These allow multiplying each of the indicated higher multipole contributions by a factor.
• Added YAW and YAW_END parameters to UKICKMAP element. It’s useful in simulating canted insertion devices.
• Added the SPEEDBUMP element, which provides a new kind of aperture formed by a semi-circular bump protruding from one or both sides of the chamber.
• Added the DX, DY, and DZ misalignment parameters to the EHKICK, EVKICK, and EKICK elements. Also added RANDOM_MULTIPOLES parameter.

13.25.4 New and Modified Commands

• Added the inelastic_scattering command, which assists in computation of the inelastic gas scattering lifetime and the distribution of lost particles. This is only available in the parallel version.
• Added the generation_interval parameter to the ion_effects command to permit generation of ions only at every n^th bunch. This was suggested by J. Calvey (APS).
• Added the ignore_elements command, which allows instructing elegant to ignore specified elements in tracking. This can reduce overhead from “do-nothing” elements like markers and monitors.
• The link_elements command can now create the source element name by editing the target name.
• The momentum_aperture command now uses resources more efficiently for the parallel version when output_mode=2. In particular, it honors the user-provided minimum δ values. In addition, the domain decomposition was revised to better equalize the workload of the processors.

13.25.5 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 developers.

• None.

13.25.6 Changes to Related Programs and Files

• Added the inelasticScatteringAnalysis script, a companion to the inelastic_scattering command in Pelegant. It allows computing the lifetime and local loss rates from inelastic gas scattering.