Fix pointer_to_next_ele to handle multipass with girders. (#2052)

Author: DavidSagan

bmad/code/pointer_to_next_ele.f90

@@ -1,12 +1,12 @@
 !+
-! Function pointer_to_next_ele (this_ele, offset, skip_beginning, follow_fork) result (next_ele)
+! Function pointer_to_next_ele (this_ele, offset, skip_beginning, follow_fork, ix_multipass) result (next_ele)
 !
 ! Function to return a pointer to the next (if offset = 1) tracking element relative to this_ele.
 ! 
-! If the this_ele is a super_lord element, the appropriate element in the tracking 
+! If the this_ele is a super_lord or girder_lord, the appropriate element in the tracking 
 ! part of the lattice is returned.
 !
-! If this_ele is a lord element but not a super_lord then this is an error since
+! If this_ele is a lord element but not a super_lord nor a girder_lord then this is an error since
 ! it is not clear what to do in this case.
 !
 ! This routine will always wrap around between branch end and branch beginning
@@ -26,12 +26,15 @@
 !                       when wrapping around. Default is False.
 !   follow_fork    -- logical, optional: If True then fork at any fork element.
 !                       Default is False.
-!
+!   ix_multipass   -- integer, optional: Default = 1. Used to select the multipass branch if
+!                       this_ele is a multipass_lord.
+!                       
+! Output:
 !   next_ele -- ele_struct, pointer: Element after this_ele (if offset = 1).
 !                Nullified if there is an error. EG bad this_ele.
 !-
 
-function pointer_to_next_ele (this_ele, offset, skip_beginning, follow_fork) result (next_ele)
+function pointer_to_next_ele (this_ele, offset, skip_beginning, follow_fork, ix_multipass) result (next_ele)
 
 use bmad_routine_interface, dummy => pointer_to_next_ele
 
@@ -42,7 +45,7 @@ function pointer_to_next_ele (this_ele, offset, skip_beginning, follow_fork) res
 type (ele_struct), pointer :: an_ele
 type (branch_struct), pointer :: branch
 
-integer, optional :: offset
+integer, optional :: offset, ix_multipass
 integer i, ix_ele, n_off
 logical, optional :: skip_beginning, follow_fork
 
@@ -65,16 +68,26 @@ function pointer_to_next_ele (this_ele, offset, skip_beginning, follow_fork) res
 ! Initially point to the first or last slave element so that this routine
 ! will return a pointer to an element that is not a slave of this_ele.
 
-if (this_ele%ix_ele > this_ele%branch%n_ele_track) then  ! Is a lord
-  if (this_ele%lord_status /= super_lord$) return    ! Error
-  if (n_off > 0) then
-    an_ele => pointer_to_slave(this_ele, this_ele%n_slave)
-  else
-    an_ele => pointer_to_slave(this_ele, 1)
-  endif
-else
-  an_ele => this_ele
-endif
+an_ele => this_ele
+
+do
+  if (an_ele%ix_ele <= an_ele%branch%n_ele_track) exit  ! Is not a lord
+
+  select case (an_ele%lord_status)
+  case (multipass_lord$)
+    an_ele => pointer_to_slave(an_ele, integer_option(1, ix_multipass))
+
+  case (super_lord$, girder_lord$)
+    if (n_off > 0) then
+      an_ele => pointer_to_slave(an_ele, an_ele%n_slave)
+    else
+      an_ele => pointer_to_slave(an_ele, 1)
+    endif
+
+  case default
+    return    ! Error
+  end select
+enddo
 
 ! Apply offset.
 ! If follow_fork = True then must check all elements in between for a possible fork element.

bmad/modules/bmad_routine_interface.f90

@@ -2189,12 +2189,12 @@ function pointer_to_multipass_lord (ele, ix_pass, super_lord) result (multi_lord
   type (ele_struct), pointer, optional :: super_lord
 end function
 
-function pointer_to_next_ele (this_ele, offset, skip_beginning, follow_fork) result (next_ele)
+function pointer_to_next_ele (this_ele, offset, skip_beginning, follow_fork, ix_multipass) result (next_ele)
   import
   implicit none
   type (ele_struct), target :: this_ele
   type (ele_struct), pointer :: next_ele
-  integer, optional :: offset
+  integer, optional :: offset, ix_multipass
   logical, optional :: skip_beginning, follow_fork
 end function
 

bmad/parsing/bmad_parser_mod.f90

@@ -1622,11 +1622,13 @@ subroutine parser_read_sr_wake (ele, delim, delim_found, err_flag)
     srz%smoothing_sigma = c_light * srz%smoothing_sigma
   endif
 
-  if (srz%smoothing_sigma /= 0) then
-    ns = max(1, nint(3*srz%smoothing_sigma / srz%dz))
+  f = srz%smoothing_sigma / srz%dz
+  ns = nint(3.0_rp * f)
+
+  if (ns /= 0) then
     allocate (gauss(-ns:ns))
     do i = -ns, ns
-      gauss(i) = exp(-0.5 * i * (srz%dz / srz%smoothing_sigma)**2)
+      gauss(i) = exp(-0.5_rp * i / f**2)
     enddo
 
     srz%fw = 0

regression_tests/multipass_test/multipass_test.f90

@@ -6,7 +6,7 @@ program multipass_test
 implicit none
 
 type (lat_struct), target :: lat, lat2
-type (ele_struct), pointer :: ele, ele2, lord
+type (ele_struct), pointer :: ele, ele0, ele2, lord, ele3, ele4
 type (ele_pointer_struct), allocatable :: eles(:)
 type (rf_stair_step_struct), pointer :: step
 
@@ -16,6 +16,26 @@ program multipass_test
 
 open (1, file = 'output.now')
 
+! Girder and multipass
+
+call bmad_parser ('multipass_with_girder.bmad', lat)
+do ie = 1, lat%n_ele_track
+  ele => lat%ele(ie)
+  ele0 => pointer_to_next_ele(ele, -1)
+  ele2 => pointer_to_next_ele(ele, 1)
+  write (1, '(3a)') quote(ele%name), ' STR ', quote(trim(ele0%name) // ' + ' // trim(ele2%name))
+enddo
+
+do ie = lat%n_ele_track+1, lat%n_ele_max
+  ele => lat%ele(ie)
+  ele0 => pointer_to_next_ele(ele, -1)
+  ele2 => pointer_to_next_ele(ele, 1)
+  ele3 => pointer_to_next_ele(ele, -1, ix_multipass = 2)
+  ele4 => pointer_to_next_ele(ele, 1, ix_multipass = 2)
+  write (1, '(3a)') quote(ele%name), ' STR ', quote(trim(ele0%name) // ' + ' // trim(ele2%name) // &
+                                                                       ' + ' // trim(ele3%name) // ' + ' // trim(ele4%name))
+enddo
+
 ! Space_charge_method test
 
 call bmad_parser ('multipass_and_superimpose.bmad', lat)
@@ -33,7 +53,6 @@ program multipass_test
 call lat_ele_locator('CAVITY1', lat, eles, n_loc)
 lord => eles(1)%ele
 
-
 do is = 0, 2
   if (is == 0) then
     ele => lord
@@ -52,8 +71,6 @@ program multipass_test
 ele => eles(1)%ele
 write (1, '(a, 2es22.14)') '"END-energy" REL 1E-8', ele%value(p0c$), ele%value(E_tot$)
 
-
-
 ! Forking with a branch element
 
 call bmad_parser ('branch_fork.bmad', lat)
@@ -83,7 +100,7 @@ program multipass_test
 write (1, '(3a)') '"MS-12"  STR  "', trim(lat%ele(12)%name), '"'
 write (1, '(3a)') '"MS-13"  STR  "', trim(lat%ele(13)%name), '"'
 
-! fiducial and flexible patch
+! Fiducial and flexible patch
 
 call bmad_parser ('patch.bmad', lat)
 call write_bmad_lattice_file ('lat_out2.bmad', lat)

regression_tests/multipass_test/multipass_with_girder.bmad

@@ -0,0 +1,19 @@
+no_digested
+
+beginning[beta_a] = 1
+beginning[beta_b] = 1
+beginning[e_tot] = 100e6
+parameter[geometry] = open
+
+f = 0
+p1: sbend, L = 1, angle = pi/2 * f, ref_tilt = pi/2
+p2: sbend, L = 2, angle = pi/2 * f
+g1: girder = {p1, p2}, x_offset = 0.001
+
+lat: line[multipass] = (p1, p2)
+lat2: line = (lat, lat)
+use, lat2
+
+m1: marker, superimpose, ref = p1
+
+

regression_tests/multipass_test/output.correct

@@ -1,3 +1,18 @@
+"P1\1#1" STR "BEGINNING + M1\1"
+"M1\1" STR "P1\1#1 + P1\1#2"
+"P1\1#2" STR "M1\1 + P2\1"
+"P2\1" STR "P1\1#2 + P1\2#1"
+"P1\2#1" STR "P2\1 + M1\2"
+"M1\2" STR "P1\2#1 + P1\2#2"
+"P1\2#2" STR "M1\2 + P2\2"
+"P2\2" STR "P1\2#2 + END"
+"END" STR "P2\2 + BEGINNING"
+"P1\1" STR "BEGINNING + P2\1 + BEGINNING + P2\1"
+"P1\2" STR "P2\1 + P2\2 + P2\1 + P2\2"
+"M1" STR "P1\1#1 + P1\1#2 + P1\2#1 + P1\2#2"
+"P2" STR "P1\1#2 + P1\2#1 + P1\2#2 + END"
+"P1" STR "BEGINNING + P2\1 + P2\1 + P2\2"
+"G1" STR "BEGINNING + P1\2#1 + P2\1 + END"
 "scm-1DRI01\1#1" STR  "Slice"  "Slice"
 "ref_time-1" ABS 1E-16  5.82081208740982E-09
 "scm-2DRI01\1\Q01\1" STR  "FFT_3D"  "FFT_3D"

regression_tests/tao_color_test/output.correct

@@ -1,22 +1,22 @@
-"css4_name" STR teal
-"css4_name_mixed_case" STR teal
-"css4_name_upper" STR teal
-"css4_name_salmon" STR salmon
-"css4_name_gold" STR gold
-"original_name" STR red
-"original_name_blue" STR blue
-"original_name_upper" STR red
-"hex_6digit" STR #FF5733
-"hex_6digit_lower" STR #FF5733
-"hex_6digit_mixed" STR #FF5733
-"hex_3digit" STR #F53
-"hex_3digit_lower" STR #ABC
-"rgb_format" STR RGB(0,128,255)
-"rgb_format_spaces" STR RGB(255,0,128)
-"rgb_lower_prefix" STR RGB(10,20,30)
-"rgb_mixed_prefix" STR RGB(1,2,3)
-"rgb_four_values" STR True
-"invalid_color_rejected" STR True
-"label_color_css4" STR teal
-"label_color_upper" STR gold
-"label_color_hex" STR #FF0000
+"css4_name" STR "teal"
+"css4_name_mixed_case" STR "teal"
+"css4_name_upper" STR "teal"
+"css4_name_salmon" STR "salmon"
+"css4_name_gold" STR "gold"
+"original_name" STR "red"
+"original_name_blue" STR "blue"
+"original_name_upper" STR "red"
+"hex_6digit" STR "#FF5733"
+"hex_6digit_lower" STR "#FF5733"
+"hex_6digit_mixed" STR "#FF5733"
+"hex_3digit" STR "#F53"
+"hex_3digit_lower" STR "#ABC"
+"rgb_format" STR "RGB(0,128,255)"
+"rgb_format_spaces" STR "RGB(255,0,128)"
+"rgb_lower_prefix" STR "RGB(10,20,30)"
+"rgb_mixed_prefix" STR "RGB(1,2,3)"
+"rgb_four_values" STR "True"
+"invalid_color_rejected" STR "True"
+"label_color_css4" STR "teal"
+"label_color_upper" STR "gold"
+"label_color_hex" STR "#FF0000"

regression_tests/tao_color_test/run.py

@@ -67,19 +67,19 @@
 
     if expected is None:
         # Expect rejection (error message)
-        results.append(f'"{label}" STR {has_error}')
+        results.append(f'"{label}" STR "{has_error}"')
     elif has_error:
-        results.append(f'"{label}" STR ERROR')
+        results.append(f'"{label}" STR "ERROR"')
     else:
-        results.append(f'"{label}" STR {actual}')
+        results.append(f'"{label}" STR "{actual}"')
 
 # Test that an invalid color produces an error (doesn't crash)
 cmd = f"set curve {curve} line%color = not_a_color;quit"
 exe = f'{bin_dir}tao -noplot -lat {lat_file} -command "{cmd}"'
 proc = subprocess.run(exe, shell=True, capture_output=True, text=True)
 # Should get an error message but not crash (exit 0)
 has_error_msg = "ERROR" in proc.stdout
-results.append(f'"invalid_color_rejected" STR {has_error_msg}')
+results.append(f'"invalid_color_rejected" STR "{has_error_msg}"')
 
 # Test label_color via python plot_graph command
 label_color_tests = [
@@ -109,9 +109,9 @@
 
     has_error = "[ERROR" in proc.stdout or proc.returncode != 0
     if has_error:
-        results.append(f'"{label}" STR ERROR')
+        results.append(f'"{label}" STR "ERROR"')
     else:
-        results.append(f'"{label}" STR {actual}')
+        results.append(f'"{label}" STR "{actual}"')
 
 # Write output.now
 with open("output.now", "w") as f:

tao/version/tao_version_mod.f90

@@ -5,5 +5,5 @@
 !-
 
 module tao_version_mod
-character(*), parameter :: tao_version_date = "2026/06/06 15:26:06"
+character(*), parameter :: tao_version_date = "2026/06/10 21:41:51"
 end module