From 81ba835d145700fb298b24c25414ca9864b7767b Mon Sep 17 00:00:00 2001
From: Giud <g_giud@mit.edu>
Date: Fri, 19 Jan 2018 10:14:43 -0500
Subject: [PATCH] if cant find cell in which particle is, calls mark_as_lost
 instead of fatal_error

---
 src/tracking.F90 | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/tracking.F90 b/src/tracking.F90
index 65769a7f18..f651517019 100644
--- a/src/tracking.F90
+++ b/src/tracking.F90
@@ -2,7 +2,7 @@ module tracking
 
   use constants
   use cross_section,      only: calculate_xs
-  use error,              only: fatal_error, warning, write_message
+  use error,              only: warning, write_message
   use geometry_header,    only: cells
   use geometry,           only: find_cell, distance_to_boundary, cross_lattice, &
                                 check_cell_overlap
@@ -85,7 +85,9 @@ contains
       if (p % coord(p % n_coord) % cell == NONE) then
         call find_cell(p, found_cell)
         if (.not. found_cell) then
-          call fatal_error("Could not locate particle " // trim(to_str(p % id)))
+          call p % mark_as_lost("Could not find the cell containing" &
+                     // " particle " // trim(to_str(p %id)))
+          return
         end if
 
         ! set birth cell attribute