Added boost header

test/external/boost/mpi/detail/computation_tree.hpp

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+// Copyright (C) 2005 Douglas Gregor.
+
+// Use, modification and distribution is subject to the Boost Software
+// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+// Compute parents, children, levels, etc. to effect a parallel
+// computation tree.
+#ifndef BOOST_MPI_COMPUTATION_TREE_HPP
+#define BOOST_MPI_COMPUTATION_TREE_HPP
+
+namespace boost { namespace mpi { namespace detail {
+
+/**
+ * @brief Aids tree-based parallel collective algorithms.
+ *
+ * Objects of this type
+ */
+class computation_tree
+{
+ public:
+  computation_tree(int rank, int size, int root, int branching_factor = -1);
+
+  /// Returns the branching factor of the tree.
+  int branching_factor() const { return branching_factor_; }
+
+  /// Returns the level in the tree on which this process resides.
+  int level() const { return level_; }
+
+  /**
+   * Returns the index corresponding to the n^th level of the tree.
+   *
+   * @param n The level in the tree whose index will be returned.
+   */
+  int level_index(int n) const;
+
+  /**
+   *  @brief Returns the parent of this process.
+   *
+   *  @returns If this process is the root, returns itself. Otherwise,
+   *  returns the process number that is the parent in the computation
+   *  tree.
+   */
+  int parent() const;
+
+  /// Returns the index for the first child of this process.
+  int child_begin() const;
+
+  /**
+   * @brief The default branching factor within the computation tree.
+   *
+   * This is the default branching factor for the computation tree, to
+   * be used by any computation tree that does not fix the branching
+   * factor itself. The default is initialized to 3, but may be
+   * changed by the application so long as all processes have the same
+   * branching factor.
+   */
+  static int default_branching_factor;
+
+ protected:
+  /// The rank of this process in the computation tree.
+  int rank;
+
+  /// The number of processes participating in the computation tree.
+  int size;
+
+  /// The process number that is acting as the root in the computation
+  /// tree.
+  int root;
+
+  /**
+   * @brief The branching factor within the computation tree.
+   *
+   * This is the default number of children that each node in a
+   * computation tree will have. This value will be used for
+   * collective operations that use tree-based algorithms.
+   */
+  int branching_factor_;
+
+  /// The level in the tree at which this process resides.
+  int level_;
+};
+
+} } } // end namespace boost::mpi::detail
+
+#endif // BOOST_MPI_COMPUTATION_TREE_HPP