Using Random Multipoles with Trajectory Correction
Posted: 30 Jun 2021, 12:34
I'm not sure what to call this, bug or working as intended, but it appears that adding random multipoles to the elements that allow it (CCBEND,KQUAD, etc) doesn't play well with trajectory correction. I've created a minimum functioning examples of the issue and attached it. The example is based on staticPlusDynamicErrors, which I found in my elegant examples directory. I added a CCBEND to the lattice, and then used &alter_elements to include random multipoles when adding static errors to the lattice, and then turn off the dynamic errors.
When I comment out the &alter_elements line, I find that the centroid trajectory during the second run matches the trajectory reported by &correct during the first run: When I leave the &alter_elements list in, the two trajectories are different: When I look through the run1-131231119.param file, I see that the random multipoles added to the CCBEND aren't recorded anywhere. So of course the two lattices will be different. From this reply it appears that those multipoles errors aren't available anywhere at all, so I can't load them into the dynamic runs.
I guess this is a feature request to get those multipoles added to the parameter or error log file. But really, I just wanted to report behavior I didn't expect in case it helps out future readers.
When I comment out the &alter_elements line, I find that the centroid trajectory during the second run matches the trajectory reported by &correct during the first run: When I leave the &alter_elements list in, the two trajectories are different: When I look through the run1-131231119.param file, I see that the random multipoles added to the CCBEND aren't recorded anywhere. So of course the two lattices will be different. From this reply it appears that those multipoles errors aren't available anywhere at all, so I can't load them into the dynamic runs.
I guess this is a feature request to get those multipoles added to the parameter or error log file. But really, I just wanted to report behavior I didn't expect in case it helps out future readers.