Backwards time tracking needed

[DavidSagan]

For the space charge calc, to track a bunch from constant t to constant s or vice versa requires backwards time tracking.

• [ ] Check bend fringes.
• [ ] Check electric and magnetic multipoles
• [ ] Check all element types

[DavidSagan]

Problem areas at this point in time:

"SAD_MULT2: Bmad_Standard-Merit"             ABS 1E-13  7.5848320000E-04
"SBEND1: Bmad_Standard-Merit"             ABS 1E-13  1.2946305773E-06
"LCAVITY1: Bmad_Standard-Merit"             ABS 1E-13  1.2381885501E-06

[DavidSagan]

@ColwynGulliford: Attached is a modified space_charge_mod.f90 file. If you want to test if this solves your problem, update to the latest bmad and use the attached file in place of the one in bmad/space_charge. Otherwise this will wait until Ningdong gets back.

@ChristopherMayes

space_charge_mod.zip

[ColwynGulliford]

Will report shortly.

[ColwynGulliford]

I tried this but get thousands of errors, all of the form:

[ERROR | 2023-MAR-21 12:01:30] track1:
    STARTING ORBIT NOT PROPERLY INITIALIZED! [NEEDS AN INIT_COORD CALL?]
    TRACKING THROUGH ELEMENT: MG.PIP03#2 (22)
[ERROR | 2023-MAR-21 12:01:30] track1:
    STARTING ORBIT NOT PROPERLY INITIALIZED! [NEEDS AN INIT_COORD CALL?]
    TRACKING THROUGH ELEMENT: MG.MAR.END (23)
[ERROR | 2023-MAR-21 12:01:30] track1:
    STARTING ORBIT NOT PROPERLY INITIALIZED! [NEEDS AN INIT_COORD CALL?]

This happens after going to my bmad directory, doing "svn update *", and then replacing the file with the one you provide. I then compile.

[DavidSagan]

@ColwynGulliford Please post your input files. Thanks.

[ColwynGulliford]

mwe.tgz

[ColwynGulliford]

Btw, I just came back to the machine I was testing that on, and I had a warning about "Out of Memory", I think due to the above issue. In order to get back to normal I had to force quit the terminal Tao was running in (it was till printing those error messages).

[DavidSagan]

@ColwynGulliford Fixed these problems. Please update to the latest code and test.