13.10 Highlights of What’s New in Version 2020.5

Here is a summary of what’s changed since release 2020.4. Historical change logs are collected in Section 13.

13.10.1 Bug Fixes for Elements

• The SCATTER element had a bug in the implementation of the ENDONPASS parameter, which was being ignored if the value was 0.
• The CCBEND element had several misalignment-related issues. Most significantly, the ETILT parameter was ignored. In addition, the sense of DX and DY was inverted when when the ANGLE was negative. As a result of these fixes, misalignment effects from CCBEND will change. Setting ETILT=0 and DX_DY_SIGN=-1 will cause the code to revert to the old behavior.

13.10.2 Bug Fixes for Commands

• Frequency map analysis would crash in some circumstances when there was a CHARGE in the beamline. This bug was reported by G. Penn (LBNL).

13.10.3 New and Modified Elements

• The BGGEXP element now supports both normal and skew components. R. Lindberg (APS) implemented the symplectic integrator option for this.
• The BMAPXYZ element now has a FSE (Fractional Strength Error) parameter.
• The RADIAL_ORDER parameter of RFTMEZ0 can now be set to 0 to turn off radial dependence of fields.
• The POLYSERIES element was released, which allows transforming the beam using a set of arbitrary polynomials in the canonical coordinates. This existed in the code but was not documented. It was developed by L. Emery (APS) and inspired by work of Y. P. Sun (APS).
• The ETILT_SIGN parameter for CSBEND, CSRCSBEND, RBEN, and SBEN now defaults to 1. The previous default of -1, for backward compatibility, was potentially confusing.

13.10.4 New and Modified Commands

• Added the change_start command, which permits changing the starting location in a lattice. This was inspired by a request from Duan Zhe (IHEP).
• The obstruction_data command now supports multiple vertical planes of data.

13.10.5 Changes Specific to the MPI Parallel Version

• None.

13.10.6 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 developers.

• None.

13.10.7 Changes to Related Programs and Files

• The computeRBGGE program was added, allowing computation of a generalized gradient expansion[50] for use with BGGEXP based on field data on a rectangular boundary [57]. The code was developed by R. Lindberg (APS) with help from R. Soliday (APS) and M. Borland (APS).