Search of closed orbit in a ring with BGGEXP elements
Posted: 01 Nov 2023, 15:23
Hello,
I am investigating the closed orbit distortion possibly created by dipoles which are all represented by BGGEXP elements obtained from numerical field data fitted by the GGE method available in elegant.
I have used the following command block for the closed orbit search:
&closed_orbit
output="%s.clo",
output_monitors_only = 0;
closed_orbit_accuracy = 1e-9,
closed_orbit_iterations = 500,
iteration_fraction = 0.1
fixed_length = 1
tracking_turns = 1
immediate = 1
&end
However, I get the following error message in running it;
error: closed orbit did not converge to better than 4.494233e+307 after 500 iterations (requirement is 1.000000e-07)
Trying secondary, tracking-based method for orbit determination (1 turn).
error: closed orbit did not converge to better than 4.494233e+307 after 500 iterations (requirement is 1.000000e-07)
statistics: ET: 02:03:40.663 CP: 154.40 BIO:0 DIO:0 PF:0 MEM:201735
Despite this message, the result that I see in "%s.clo" appears all normal with the found trajectory well fulfilling the periodicity, as well as showing good convergence in the closed orbit search (please see the attachment).
I would therefore like to know whether I can trust the result obtained and whether you see why I get this error message.
Thanking you in advance for your kind help,
R. Nagaoka
I am investigating the closed orbit distortion possibly created by dipoles which are all represented by BGGEXP elements obtained from numerical field data fitted by the GGE method available in elegant.
I have used the following command block for the closed orbit search:
&closed_orbit
output="%s.clo",
output_monitors_only = 0;
closed_orbit_accuracy = 1e-9,
closed_orbit_iterations = 500,
iteration_fraction = 0.1
fixed_length = 1
tracking_turns = 1
immediate = 1
&end
However, I get the following error message in running it;
error: closed orbit did not converge to better than 4.494233e+307 after 500 iterations (requirement is 1.000000e-07)
Trying secondary, tracking-based method for orbit determination (1 turn).
error: closed orbit did not converge to better than 4.494233e+307 after 500 iterations (requirement is 1.000000e-07)
statistics: ET: 02:03:40.663 CP: 154.40 BIO:0 DIO:0 PF:0 MEM:201735
Despite this message, the result that I see in "%s.clo" appears all normal with the found trajectory well fulfilling the periodicity, as well as showing good convergence in the closed orbit search (please see the attachment).
I would therefore like to know whether I can trust the result obtained and whether you see why I get this error message.
Thanking you in advance for your kind help,
R. Nagaoka