Minor restructuring in source module, added copy_source_attributes subroutine. Moved count for total_weight into transport module.

src/DEPENDENCIES

@@ -65,6 +65,7 @@ fixed_source.o: constants.o
 fixed_source.o: global.o
 fixed_source.o: output.o
 fixed_source.o: physics.o
+fixed_source.o: random_lcg.o
 fixed_source.o: source.o
 fixed_source.o: string.o
 fixed_source.o: tally.o

src/fixed_source.F90

@@ -4,24 +4,29 @@ module fixed_source
   use global
   use output,     only: write_message, header
   use physics,    only: transport
-  use source,     only: get_source_particle
+  use random_lcg, only: set_particle_seed
+  use source,     only: initialize_particle, sample_external_source, &
+                        copy_source_attributes
   use string,     only: to_str
   use tally,      only: synchronize_tallies
   use timing,     only: timer_start, timer_stop
 
+  type(Bank), pointer :: source_site => null()
+
 contains
 
   subroutine run_fixedsource()
 
-    integer(8) :: i  ! index over histories in single cycle
+    integer(8) :: i ! index over histories in single cycle
 
     if (master) call header("BEGIN SIMULATION", level=1)
 
     tallies_on = .true.
     call timer_start(time_inactive)
 
-    ! Allocate particle
+    ! Allocate particle and dummy source site
     allocate(p)
+    allocate(source_site)
 
     ! ==========================================================================
     ! LOOP OVER BATCHES
@@ -36,8 +41,19 @@ contains
        ! LOOP OVER PARTICLES
        PARTICLE_LOOP: do i = 1, work
 
+          ! Set unique particle ID
+          p % id = (current_batch - 1)*n_particles + bank_first + i - 1
+
+          ! set particle trace
+          trace = .false.
+          if (current_batch == trace_batch .and. current_gen == trace_gen .and. &
+               bank_first + i - 1 == trace_particle) trace = .true.
+
+          ! set random number seed
+          call set_particle_seed(p % id)
+          
           ! grab source particle from bank
-          call get_source_particle(i)
+          call sample_source_particle()
 
           ! transport particle
           call transport()
@@ -76,4 +92,21 @@ contains
 
   end subroutine initialize_batch
 
+!===============================================================================
+! SAMPLE_SOURCE_PARTICLE
+!===============================================================================
+
+  subroutine sample_source_particle()
+
+    ! Set particle
+    call initialize_particle()
+
+    ! Sample the external source distribution
+    call sample_external_source(source_site)
+
+    ! Copy source attributes to the particle
+    call copy_source_attributes(source_site)
+
+  end subroutine sample_source_particle
+
 end module fixed_source

src/physics.F90

@@ -41,13 +41,17 @@ contains
     logical :: found_cell      ! found cell which particle is in?
     type(LocalCoord), pointer :: coord => null()
 
+    ! Display message if high verbosity or trace is on
     if (verbosity >= 9 .or. trace) then
        message = "Simulating Particle " // trim(to_str(p % id))
        call write_message()
     end if
 
+    ! If the cell hasn't been determined based on the particle's location,
+    ! initiate a search for the current cell
     if (p % coord % cell == NONE) then
        call find_cell(found_cell)
+
        ! Particle couldn't be located
        if (.not. found_cell) then
           message = "Could not locate particle " // trim(to_str(p % id))
@@ -61,6 +65,9 @@ contains
     ! Initialize number of events to zero
     n_event = 0
 
+    ! Add paricle's starting weight to count for normalizing tallies later
+    total_weight = total_weight + p % wgt
+
     ! Force calculation of cross-sections by setting last energy to zero 
     micro_xs % last_E = ZERO
 

src/source.F90

@@ -28,6 +28,8 @@ contains
     integer(8) :: i          ! loop index over bank sites
     integer(8) :: id         ! particle id
 
+    type(Bank), pointer :: src => null() ! source bank site
+
     message = "Initializing source particles..."
     call write_message(6)
 
@@ -40,17 +42,21 @@ contains
     else
        ! Generation source sites from specified distribution in user input
        do i = 1, work
+          ! Get pointer to source bank site
+          src => source_bank(i)
+
+          ! Set ID of source bank site
           id = bank_first + i - 1
-          source_bank(i) % id = id
+          src % id = id
 
           ! Set weight to one
-          source_bank(i) % wgt = ONE
+          src % wgt = ONE
 
           ! initialize random number seed
           call set_particle_seed(id)
 
           ! sample external source distribution
-          call sample_external_source(source_bank(i))
+          call sample_external_source(src)
        end do
     end if
  
@@ -62,7 +68,7 @@ contains
 
   subroutine sample_external_source(site)
 
-    type(Bank), intent(inout) :: site ! source site
+    type(Bank), pointer :: site ! source site
 
     integer :: i          ! dummy loop index
     real(8) :: r(3)       ! sampled coordinates
@@ -73,6 +79,9 @@ contains
     real(8) :: a          ! Arbitrary parameter 'a'
     real(8) :: b          ! Arbitrary parameter 'b'
 
+    ! Set weight to one by default
+    site % wgt = ONE
+
     ! Sample position
     select case (external_source % type_space)
     case (SRC_SPACE_BOX)
@@ -155,17 +164,9 @@ contains
     ! set defaults
     call initialize_particle()
 
-    ! point to next source particle
+    ! Copy attributes from source to particle
     src => source_bank(index_source)
-
-    ! copy attributes from source bank site
-    p % wgt         = src % wgt
-    p % last_wgt    = src % wgt
-    p % coord % xyz = src % xyz
-    p % coord % uvw = src % uvw
-    p % last_xyz    = src % xyz
-    p % E           = src % E
-    p % last_E      = src % E
+    call copy_source_attributes(src)
 
     ! set identifier for particle
     p % id = bank_first + index_source - 1
@@ -180,11 +181,27 @@ contains
     if (current_batch == trace_batch .and. current_gen == trace_gen .and. &
          p % id == trace_particle) trace = .true.
 
-    ! Add paricle's starting weight to count for normalizing tallies later
-    total_weight = total_weight + src % wgt
-
   end subroutine get_source_particle
 
+!===============================================================================
+! COPY_SOURCE_ATTRIBUTES
+!===============================================================================
+
+  subroutine copy_source_attributes(src)
+
+    type(Bank), pointer :: src
+
+    ! copy attributes from source bank site
+    p % wgt         = src % wgt
+    p % last_wgt    = src % wgt
+    p % coord % xyz = src % xyz
+    p % coord % uvw = src % uvw
+    p % last_xyz    = src % xyz
+    p % E           = src % E
+    p % last_E      = src % E
+
+  end subroutine copy_source_attributes
+
 !===============================================================================
 ! INITIALIZE_PARTICLE sets default attributes for a particle from the source
 ! bank