Merge pull request #733 from bmad-sim/devel/89

Fix linear beambeam spin tracking.

bmad/low_level/track1_spin_bmad.f90

@@ -32,6 +32,8 @@ subroutine track1_spin_bmad (start_orb, ele, param, end_orb)
 
 real(rp) spline_x(0:3), spline_y(0:3), omega(3), s_edge_track
 real(rp) voltage, k_rf, phase
+real(rp) fc, dxp, dyp, om(3), quat(0:3)
+
 integer key, dir
 
 character(*), parameter :: r_name = 'track1_spin_bmad'
@@ -40,6 +42,20 @@ subroutine track1_spin_bmad (start_orb, ele, param, end_orb)
 
 if (ele%key == patch$) return
 
+! Beambeam
+
+if (ele%key == beambeam$) then
+ fc = start_orb%p0c / ((1.0_rp + start_orb%beta**2) * charge_of(start_orb%species))
+ dxp = (end_orb%vec(2) - start_orb%vec(2)) * fc
+ dyp = (end_orb%vec(4) - start_orb%vec(4)) * fc
+ field%E = [dxp, dyp, 0.0_rp]
+ field%B = [dyp, -dxp, 0.0_rp] / c_light
+ om = spin_omega (field, end_orb, +1)
+ quat = omega_to_quat(om)
+ end_orb%spin = quat_rotate(quat, start_orb%spin)
+ return
+endif
+
 ! crab_cavity
 
 if (ele%key == crab_cavity$) then

bmad/low_level/track_a_beambeam.f90

@@ -146,7 +146,7 @@ subroutine track_a_beambeam (orbit, ele, param, track, mat6, make_matrix)
 
  if (bmad_com%spin_tracking_on) then
  ff = 1.0_rp + orbit%beta**2
- field%E = [ k0_x, k0_y, 0.0_rp] * (coef * orbit%p0c / (ff * charge_of(orbit%species)))
+ field%E = [k0_x,  k0_y, 0.0_rp] * (coef * orbit%p0c / (ff * charge_of(orbit%species)))
  field%B = [k0_y, -k0_x, 0.0_rp] * (coef * orbit%p0c * orbit%beta / (ff * c_light * charge_of(orbit%species)))
  om = spin_omega (field, orbit, +1)
  quat = omega_to_quat(om)

bsim/modules/lt_tracking_mod.f90

@@ -43,6 +43,7 @@ module lt_tracking_mod
  character(100) :: exclude_from_maps = 'beambeam::*'
  character(40) :: ele_start = ''
  character(40) :: ele_stop = ''
+ character(40) :: ele_extract = ''
  character(200) :: lat_file = ''
  character(200) :: beam_binary_output_file = ''
  character(200) :: custom_output_file = ''
@@ -239,25 +240,33 @@ subroutine ltt_read_params(ltt, ltt_com)
 
 if (ltt%master_output_file /= '') then
  call out_io (s_info$, r_name, &
- 'Note: The master_output_file is no longer created since data in this file is written to other files.')
+ 'Note: The master_output_file is no longer created since data in this file is written to other files.', &
+ 'Please correct the init file. Will stop here.')
+ stop
 endif
 
 if (ltt%sigma_matrix_output_file /= '') then
  call out_io (s_info$, r_name, &
- 'Note: ltt%sigma_matrix_output_file is no longer used and will be ignored.', &
+ 'Note: ltt%sigma_matrix_output_file is no longer used.', &
  ' Essentially now ltt%averages_output_file sets the name of the sigma matrix file.', &
- ' See manual for details.')
+ ' See manual for details.', &
+ ' Please correct the init file. Will stop here.')
+ stop
 endif
 
 if (ltt%averaging_window /= 1) then
  call out_io (s_info$, r_name, &
- 'Note: ltt%averaging_window is no longer used and will be ignored.', &
+ 'Note: ltt%averaging_window is no longer used.', &
  ' Reason: The advantage of averaging over multiple turns was not worth the complications', &
- ' to the program internal bookkeeping') 
+ ' to the program internal bookkeeping', &
+ 'Please correct the init file. Will stop here.')
+ stop
 endif
 
 if (ltt%mpi_runs_per_subprocess /= 4) then
- call out_io (s_info$, r_name, 'Note: ltt%mpi_runs_per_subprocess is no longer used and will be ignored.')
+ call out_io (s_info$, r_name, 'Note: ltt%mpi_runs_per_subprocess is no longer used.', &
+ 'Please correct the init file. Will stop here.')
+ stop
 endif
 
 if (any(ltt%core_emit_cutoff > 1.00000001_rp .or. &
@@ -268,8 +277,9 @@ subroutine ltt_read_params(ltt, ltt_com)
 
 if (ltt%particle_output_file /= '') then
  call out_io (s_error$, r_name, 'Note: ltt%particle_output_file replaced by ltt%phase_space_output_file.', &
- ' Also see ltt%action_angle_output_file.')
- ltt%phase_space_output_file = ltt%particle_output_file
+ ' Also see ltt%action_angle_output_file.', &
+ 'Please correct the init file. Will stop here.')
+ stop
 endif
 
 end subroutine ltt_read_params

regression_tests/backwards_time_track_test/output.correct

@@ -119,11 +119,11 @@
 "BEAMBEAM1: Bmad_Standard-c*dt,dp0c,ds,dbeta" ABS 2e-12 0.0000000000E+00 0.0000000000E+00 0.0000000000E+00 0.0000000000E+00
 "BEAMBEAM1: Bmad_Standard-Merit" ABS 2e-12 2.6114488350E-10
 "BEAMBEAM1: Linear-end" ABS 2e-12 1.0000000000E-03 2.3545039161E-03 3.0000000000E-03 4.3424403052E-03 5.0000000000E-03 6.0000000000E-03 6.9608944983E-01
-"BEAMBEAM1: Linear-dendSpin" ABS 2e-12 0.0000000000E+00 0.0000000000E+00 0.0000000000E+00
+"BEAMBEAM1: Linear-dendSpin" ABS 2e-12 1.5942634489E-04 1.5383726718E-04 -2.1882258667E-04
 "BEAMBEAM1: Linear-dOrb" ABS 2e-12 0.0000000000E+00 0.0000000000E+00 0.0000000000E+00 0.0000000000E+00 0.0000000000E+00 0.0000000000E+00
-"BEAMBEAM1: Linear-dSpin" ABS 2e-12 0.0000000000E+00 0.0000000000E+00 0.0000000000E+00
+"BEAMBEAM1: Linear-dSpin" ABS 2e-12 2.2063673111E-10 2.1293194985E-10 -3.0272701013E-10
 "BEAMBEAM1: Linear-c*dt,dp0c,ds,dbeta" ABS 2e-12 0.0000000000E+00 0.0000000000E+00 0.0000000000E+00 0.0000000000E+00
-"BEAMBEAM1: Linear-Merit" ABS 2e-12 0.0000000000E+00
+"BEAMBEAM1: Linear-Merit" ABS 2e-12 3.0272701013E-10
 "BEAMBEAM1: Taylor-end" ABS 2e-12 1.0000000000E-03 2.3055627573E-03 3.0000000000E-03 4.2942285396E-03 5.0000000000E-03 6.0000000000E-03 6.9608944983E-01
 "BEAMBEAM1: Taylor-dendSpin" ABS 2e-12 1.2526671792E-04 1.2047877699E-04 -1.7160270672E-04
 "BEAMBEAM1: Taylor-dOrb" ABS 2e-12 0.0000000000E+00 0.0000000000E+00 0.0000000000E+00 8.6736173799E-19 0.0000000000E+00 0.0000000000E+00