DRIFT vs CSRDRIFT vs EDRIFT vs LSCDRIFT

[frank_stulle]

Hello,
besides LSC in the LSCDRIFT and CSR in the CSRDRIFT, what are the differences between these drifts?

Best regards
Frank

[michael_borland]

Frank,

The DRIFT element type is a matrix implementation, up to second order. (The second order terms are the path-length dependence on slope.)

EDRIFT is an Exact DRIFT. Instead of using a matrix it just computes the exact path length effect. On modern hardware, square roots are very fast so I'd guess there is little performance reduction from this. CSRDRIFT and LSCDRIFT, in addition to including CSR and LSC, also perform exact drifting.

--Michael

[frank_stulle]

Thanks, that's already good to know. But now I am in trouble, because you say EDRIFT, CSRDRIFT and LSCDRIFT all use exact drifting. I have a lattice with long drifts and arcs. The difference between using DRIFT and CSRDRIFT is negligible. But when I use EDRIFT I get some strange emittance growth in the following arcs. I will prepare some test case which shows this behavior.

Frank

[frank_stulle]

Well... I just made a stupid mistake in my input files and then made a wrong interpretation of the cause of the strange output I got. So, forget what I wrote, everything is fine.

Frank

[michael_borland]

Frank,

No problem. It is always good to test any program and I'm happy to hear it was alright in the end.

--Michael