Add option to set number of threads in settings.xml and command line.

src/global.F90

@@ -212,7 +212,7 @@ module global
   integer :: MPI_TALLYRESULT       ! MPI datatype for TallyResult
 
 #ifdef OPENMP
-  integer :: n_threads             ! number of OpenMP threads
+  integer :: n_threads = NONE      ! number of OpenMP threads
   integer :: thread_id             ! ID of a given thread
 #endif
 

src/initialize.F90

@@ -367,6 +367,23 @@ contains
         case ('-g', '-geometry-debug', '--geometry-debug')
           check_overlaps = .true.
 
+        case ('-t', '--threads')
+          ! Read number of threads
+          i = i + 1
+
+#ifdef OPENMP          
+          ! Read and set number of OpenMP threads
+          n_threads = str_to_int(argv(i))
+          if (n_threads < 1) then
+            message = "Invalid number of threads specified on command line."
+            call fatal_error()
+          end if
+          call omp_set_num_threads(n_threads)
+#else
+          message = "Ignoring number of threads specified on command line."
+          call warning()
+#endif
+
         case ('-?', '-help', '--help')
           call print_usage()
           stop

src/input_xml.F90

@@ -73,6 +73,7 @@ contains
     cross_sections_ = ''
     output_path_ = ''
     verbosity_ = 0
+    threads_ = NONE
     energy_grid_ = 'union'
     seed_ = 0_8
     source_ % file = ''
@@ -207,6 +208,23 @@ contains
     ! Verbosity
     if (verbosity_ > 0) verbosity = verbosity_
 
+    ! Number of OpenMP threads
+    if (threads_ /= NONE) then
+#ifdef OPENMP
+      if (n_threads == NONE) then
+        n_threads = threads_
+        if (n_threads < 1) then
+          message = "Invalid number of threads: " // to_str(n_threads)
+          call fatal_error()
+        end if
+        call omp_set_num_threads(n_threads)
+      end if
+#else
+      message = "Ignoring number of threads."
+      call warning()
+#endif
+    end if
+
     ! ==========================================================================
     ! EXTERNAL SOURCE
 

src/output.F90

@@ -170,6 +170,7 @@ contains
       write(OUTPUT_UNIT,*) '  -p, --plot             Run in plotting mode'
       write(OUTPUT_UNIT,*) '  -r, --restart          Restart a previous run from a state point'
       write(OUTPUT_UNIT,*) '                         or a particle restart file'
+      write(OUTPUT_UNIT,*) '  -t, --threads          Number of OpenMP threads'
       write(OUTPUT_UNIT,*) '  -v, --version          Show version information'
       write(OUTPUT_UNIT,*) '  -?, --help             Show this message'
     end if

src/templates/settings.rnc

@@ -97,6 +97,8 @@ element settings {
 
   element survival_biasing { xsd:boolean }? &
 
+  element threads { xsd:positiveInteger }? &
+
   element trace { list { xsd:positiveInteger+ } }? &
 
   element verbosity { xsd:positiveInteger }? &

src/templates/settings_t.xml

@@ -58,6 +58,7 @@
   <variable name="source_" tag="source" type="source_xml" />
   <variable name="state_point_" tag="state_point" type="statepoint_xml" dimension="1" />
   <variable name="survival_" tag="survival_biasing" type="word" length="5" />
+  <variable name="threads_" tag="threads" type="integer" />
   <variable name="trace_" tag="trace" type="integer-array" />
   <variable name="uniform_fs_" tag="uniform_fs" type="mesh_xml" dimension="1" />
   <variable name="verbosity_" tag="verbosity" type="integer" />