CarpetLib: Set number of OpenMP threads via an external function call

Set the number of OpenMP threads via an external function call instead
of via a CarpetLib parameter.

darcs-hash:20080114150439-dae7b-a6a6a629162ca195411852823e1ece0a2071d771.gz

3 files changed, 15 insertions, 25 deletions

diff --git a/Carpet/CarpetLib/param.ccl b/Carpet/CarpetLib/param.ccl
index 4ed749066..f058923a2 100644
--- a/Carpet/CarpetLib/param.ccl
+++ b/Carpet/CarpetLib/param.ccl
@@ -23,14 +23,6 @@ BOOLEAN barriers "Insert barriers at strategic places for debugging purposes (sl
 
 
 
-CCTK_INT num_threads "Number of threads per process" STEERABLE=recover
-{
-  -1  :: "use system default, probably influenced by OMP_NUM_THREADS"
-  1:* :: "use this many threads"
-} -1
-
-
-
 BOOLEAN output_bboxes "Output bounding box information to the screen" STEERABLE=always
 {
 } "no"
diff --git a/Carpet/CarpetLib/src/dist.cc b/Carpet/CarpetLib/src/dist.cc
index 1af4bcf38..7ac6f73f6 100644
--- a/Carpet/CarpetLib/src/dist.cc
+++ b/Carpet/CarpetLib/src/dist.cc
@@ -1,9 +1,9 @@
 #include <cassert>
 
+#include <mpi.h>
 #ifdef _OPENMP
 #  include <omp.h>
 #endif
-#include <mpi.h>
 
 #include "cctk.h"
 #include "cctk_Parameters.h"
@@ -66,33 +66,21 @@ namespace dist {
     }
   }
   
-  // Local number of threads
-  int num_threads_worker ()
+  // Set number of threads
+  void set_num_threads (int const num_threads)
   {
-    DECLARE_CCTK_PARAMETERS;
-    int num_threads_;
 #ifdef _OPENMP
     if (num_threads > 0) {
       // Set number of threads which should be used
       // TODO: do this at startup, not in this routine
       omp_set_num_threads (num_threads);
     }
-#pragma omp parallel
-    {
-#pragma omp single nowait
-      {
-        num_threads_ = omp_get_num_threads();
-      }
-    }
 #else
     if (num_threads > 0 and num_threads != 1) {
       CCTK_WARN (CCTK_WARN_ABORT,
                  "OpenMP is not enabled.  Cannot set the number of threads.");
     }
-    num_threads_ = 1;
 #endif
-    assert (num_threads_ >= 1);
-    return num_threads_;
   }
   
   // Global number of threads
diff --git a/Carpet/CarpetLib/src/dist.hh b/Carpet/CarpetLib/src/dist.hh
index 1206901e3..7d501c857 100644
--- a/Carpet/CarpetLib/src/dist.hh
+++ b/Carpet/CarpetLib/src/dist.hh
@@ -6,6 +6,9 @@
 #include <cstdlib>
 
 #include <mpi.h>
+#ifdef _OPENMP
+#  include <omp.h>
+#endif
 
 #include "cctk.h"
 
@@ -63,13 +66,20 @@ namespace dist {
     return size_;
   }
   
+  // Set number of threads
+  void set_num_threads (int num_threads);
+  
   // Local number of threads
-  int num_threads_worker ();
   inline int num_threads ()
   {
     static int num_threads_ = -1;
     if (num_threads_ == -1) {
-      num_threads_ = num_threads_worker();
+#ifdef _OPENMP
+      num_threads_ = omp_get_max_threads();
+#else
+      num_threads_ = 1;
+#endif
+      assert (num_threads_ >= 1);
     }
     return num_threads_;
   }