From a272bafb03d0c4ea1b5dee5bb41649e99691da42 Mon Sep 17 00:00:00 2001
From: Paul Romano <romano7@gmail.com>
Date: Thu, 22 Mar 2012 10:38:11 -0400
Subject: [PATCH] Added trace information on collision.

---
 src/geometry.F90        |  2 +-
 src/particle_header.F90 |  3 ++-
 src/physics.F90         | 18 +++++++++++++++---
 3 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/src/geometry.F90 b/src/geometry.F90
index fe75d2c4e6..0abda64c13 100644
--- a/src/geometry.F90
+++ b/src/geometry.F90
@@ -137,7 +137,7 @@ contains
           p % coord % cell = index_cell
 
           ! Show cell information on trace
-          if (trace) then
+          if (verbosity >= 10 .or. trace) then
              message = "    Entering cell " // trim(to_str(c % id))
              call write_message()
           end if
diff --git a/src/particle_header.F90 b/src/particle_header.F90
index a9cfa12c24..4330dfb882 100644
--- a/src/particle_header.F90
+++ b/src/particle_header.F90
@@ -52,7 +52,8 @@ module particle_header
      real(8)    :: last_E        ! last energy
 
      ! What event last took place
-     integer    :: event
+     integer    :: event         ! scatter, absorption, fission
+     integer    :: event_nuclide ! index in nuclides array
 
      ! Post-collision physical data
      integer    :: n_bank        ! number of fission sites banked
diff --git a/src/physics.F90 b/src/physics.F90
index a553a115d8..27ec0adc20 100644
--- a/src/physics.F90
+++ b/src/physics.F90
@@ -182,9 +182,18 @@ contains
 
     ! Display information about collision
     if (verbosity >= 10 .or. trace) then
-!!$       message = "    " // trim(reaction_name(MT)) // ". Energy = " // &
-!!$            trim(to_str(p % E * 1e6_8)) // " eV."
-!!$       call write_message()
+       select case (p % event)
+       case (EVENT_SCATTER)
+          message = "    Scattered off of"
+       case (EVENT_FISSION)
+          message = "    Fissioned in"
+       case (EVENT_ABSORB)
+          message = "    Absorbed in"
+       end select
+       message = trim(message) // " " // trim(nuclides(&
+            p % event_nuclide) % name) // ". Energy = " // &
+            trim(to_str(p % E * 1e6_8)) // " eV." 
+       call write_message()
     end if
 
     ! check for very low energy
@@ -262,6 +271,9 @@ contains
     IE  =  micro_xs(index_nuclide) % index_grid
     f   =  micro_xs(index_nuclide) % interp_factor
 
+    ! Save which nuclide particle had collision with
+    p % event_nuclide = index_nuclide
+
     ! ==========================================================================
     ! DISAPPEARANCE REACTIONS (ANALOG) OR IMPLICIT CAPTURE (SURVIVAL BIASING)