number of cpus is detected on linux and sun

git-svn-id: https://svn.dealii.org/trunk@2487 0785d39b-7218-0410-832d-ea1e28bc413d

diff --git a/deal.II/base/include/base/multithread_info.h b/deal.II/base/include/base/multithread_info.h
new file mode 100644 (file)
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--- /dev/null
+++ b/deal.II/base/include/base/multithread_info.h
@@ -0,0 +1,92 @@
+//----------------------------   multithread_info.h     ---------------------------
+//    $Id$
+//    Version: $Name$
+//
+//    Copyright (C) 1998, 1999, 2000 by the deal.II authors
+//
+//    This file is subject to QPL and may not be  distributed
+//    without copyright and license information. Please refer
+//    to the file deal.II/doc/license.html for the  text  and
+//    further information on this license.
+//
+//----------------------------   multithread_info.h     ---------------------------
+#ifndef __deal2__multithread_info_h
+#define __deal2__multithread_info_h
+//----------------------------   multithread_info.h     ---------------------------
+
+
+#include <base/exceptions.h>
+
+
+/**
+ * This class provides information about the system.
+ * At the moment this is just the number of cpus. If deal is
+ * compiled with multithreading support,  all functions with
+ * use #n_default_threads# as the default number of threads
+ * to start all functions.
+ * This variable #n_default_threads# is set to the number of
+ * cpus per default, but can be adjusted by the user to fit
+ * the requirements.
+ */
+class MultithreadInfo {
+  public:
+                                    /**
+                                     * The constructor determines the
+                                     * number of cpus in the system.
+                                     * At the moment detection of cpus
+                                     * is only impelented on Linux
+                                     * computers with the proc filesystem
+                                     * and on suns.
+                                     * Other platforms will hopefully follow.
+                                     * The number of cpus present is set to
+                                     * one if detection failed or if
+                                     * detection is not supported.
+                                     */
+    MultithreadInfo();
+
+                                    /**
+                                     * The number of cpus in the system.
+                                     * It is one, if detection is not implemented.
+                                     */
+    const unsigned int n_cpus;
+
+                                    /**
+                                     * The number of threads to use as
+                                     * a default value for all functions
+                                     * that support multithreading.
+                                     * At start time this is #n_cpus# or
+                                     * one, if detection of the number
+                                     * of cpus is not possibly
+                                     */
+    unsigned int n_default_threads;
+
+                                    /**
+                                     * Exception
+                                     */
+    DeclException0(ExcProcNotPresent);
+    
+    
+  private:
+
+                                    /**
+                                     * Private function to determine
+                                     * the number of cpus.
+                                     * Implementation for Linux and suns.
+                                     */
+    static unsigned int get_n_cpus();
+};
+
+
+                                
+extern MultithreadInfo multithread_info;
+
+
+
+
+//----------------------------   multithread_info.h     ---------------------------
+// end of #ifndef __deal2__multithread_info_h
+#endif
+//----------------------------   multithread_info.h     ---------------------------
+
+
+