There is a bug in the LSRMDLTR element when the field expansion is set to "leading-terms" or "exact". The longitudinal magnetic field has the wrong sign, leading to incorrect vertical focusing. For those who build from source, a corrected file is attached. This fix will appear in the next release.
Thanks to Dao Xiang (SLAC) for alerting me to the problem.
--Michael
Bug in LSRMDLTR
Moderators: michael_borland, soliday
-
- Posts: 1951
- Joined: 19 May 2008, 09:33
- Location: Argonne National Laboratory
- Contact:
Bug in LSRMDLTR
- Attachments
-
- motion.c
- (82.59 KiB) Downloaded 1302 times
Re: Bug in LSRMDLTR
Hi Michael,
I find this bug show up again in version 26.0.2, with incorrect vertical focusing when the field expansion is set to "leading-terms" or "exact".
Zhen
I find this bug show up again in version 26.0.2, with incorrect vertical focusing when the field expansion is set to "leading-terms" or "exact".
Zhen
-
- Posts: 1951
- Joined: 19 May 2008, 09:33
- Location: Argonne National Laboratory
- Contact:
Re: Bug in LSRMDLTR
Zhen,
I tested LSRMDLTR against WIGGLER and CWIGGLER, and the focusing seems correct for both "leading terms" and "exact" expansions. Can you check again, and send an example input file that shows the problem?
Thanks--Michael
I tested LSRMDLTR against WIGGLER and CWIGGLER, and the focusing seems correct for both "leading terms" and "exact" expansions. Can you check again, and send an example input file that shows the problem?
Thanks--Michael
Re: Bug in LSRMDLTR
Michael,
Attached please find the input files of LSRMDLTR. For different FIELD_EXPANSION I found the final phase space t-yp and y-yp were different. There were vertical focusing when it was "leading terms" or "exact". The code version is 26.0.2 on the oak cluster of SLAC.
Thanks.
Zhen
Attached please find the input files of LSRMDLTR. For different FIELD_EXPANSION I found the final phase space t-yp and y-yp were different. There were vertical focusing when it was "leading terms" or "exact". The code version is 26.0.2 on the oak cluster of SLAC.
Thanks.
Zhen
- Attachments
-
- modulator.lte
- (524 Bytes) Downloaded 335 times
-
- modulator.ele
- (2.11 KiB) Downloaded 311 times
-
- Posts: 1951
- Joined: 19 May 2008, 09:33
- Location: Argonne National Laboratory
- Contact:
Re: Bug in LSRMDLTR
Zhen,
If I turn the laser off, I can compare the results to other methods in elegant. Doing this shows nearly exact agreement between the LSRMDLTR (exact and leading-terms modes) and CWIGGLER elements, which are implemented in completely different ways (by different people). So I think the LSRMDLTR is getting the focusing correct. It "ideal" method of course is not correct.
Am I missing something?
--Michael
If I turn the laser off, I can compare the results to other methods in elegant. Doing this shows nearly exact agreement between the LSRMDLTR (exact and leading-terms modes) and CWIGGLER elements, which are implemented in completely different ways (by different people). So I think the LSRMDLTR is getting the focusing correct. It "ideal" method of course is not correct.
Am I missing something?
--Michael