Calculation of 2nd order Taylor terms affected by including markers

bmad-sim / pytao

PyTao is Python interface for Tao, which is based on the Bmad subroutine library for relativistic charged–particle and X-ray simulations in accelerators and storage rings.

https://bmad-sim.github.io/pytao

GNU General Public License v3.0

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Calculation of 2nd order Taylor terms affected by including markers #66

Closed weiyuanlou closed 3 months ago

weiyuanlou commented 1 year ago

Hi Dave, attached lattice is a short line with few sbends, quads, and sextuples. You can do sho Taylor -order 2 to see the tt.xxx terms. However if you insert markers ( by un-commenting the 2nd last line in lat.bmad ) , then these terms differ. For instance, the t566 term changes from -1.61 m to -1.60 m.

Is this supposed to happen with PTC calculation? Thanks.

lat.zip

DavidSagan commented 3 months ago

@weiyuanlou I don't normally look at the pytao issue forum so I did not see this until now. Please open an issue on bmad-ecosystem and I will take a look.