utilities.h

// ---------------------------------------------------------------------
//
// Copyright (C) 2005 - 2016 by the deal.II authors
//
// This file is part of the deal.II library.
//
// The deal.II library is free software; you can use it, redistribute
// it, and/or modify it under the terms of the GNU Lesser General
// Public License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
// The full text of the license can be found in the file LICENSE at
// the top level of the deal.II distribution.
//
// ---------------------------------------------------------------------

#ifndef dealii__utilities_h
#define dealii__utilities_h

#include <deal.II/base/config.h>
#include <deal.II/base/exceptions.h>

#include <vector>
#include <utility>
#include <functional>
#include <string>

#ifdef DEAL_II_WITH_TRILINOS
#  include <Epetra_Comm.h>
#  include <Epetra_Map.h>
#  ifdef DEAL_II_WITH_MPI
#    include <Epetra_MpiComm.h>
#  else
#    include <Epetra_SerialComm.h>
#  endif
#endif

DEAL_II_NAMESPACE_OPEN


namespace Utilities
{

  std::string
  int_to_string (const unsigned int value,
                 const unsigned int digits = numbers::invalid_unsigned_int);

  template <typename number>
  std::string
  to_string (const number value,
             const unsigned int digits = numbers::invalid_unsigned_int);

  unsigned int
  needed_digits (const unsigned int max_number);

  int
  string_to_int (const std::string &s);

  std::string dim_string(const int dim, const int spacedim);

  std::vector<int>
  string_to_int (const std::vector<std::string> &s);

  double
  string_to_double (const std::string &s);


  std::vector<double>
  string_to_double (const std::vector<std::string> &s);

  std::vector<std::string>
  split_string_list (const std::string &s,
                     const char         delimiter = ',');

  std::vector<std::string>
  break_text_into_lines (const std::string &original_text,
                         const unsigned int width,
                         const char delimiter = ' ');

  bool
  match_at_string_start (const std::string &name,
                         const std::string &pattern);

  std::pair<int, unsigned int>
  get_integer_at_position (const std::string &name,
                           const unsigned int position);

  std::string replace_in_string(const std::string &input,
                                const std::string &from,
                                const std::string &to);

  std::string
  trim(const std::string &input);

  double
  generate_normal_random_number (const double a,
                                 const double sigma);


  template <int N, typename T>
  T
  fixed_power (const T t);

  template <int a, int N>
  struct fixed_int_power
  {
    static const int value = a *fixed_int_power<a,N-1>::value;
  };

  template <int a>
  struct fixed_int_power<a,0>
  {
    static const int value = 1;
  };

  template<typename Iterator, typename T>
  Iterator
  lower_bound (Iterator  first,
               Iterator  last,
               const T  &val);


  template<typename Iterator, typename T, typename Comp>
  Iterator
  lower_bound (Iterator   first,
               Iterator   last,
               const T   &val,
               const Comp comp);

  std::vector<unsigned int>
  reverse_permutation (const std::vector<unsigned int> &permutation);

  std::vector<unsigned int>
  invert_permutation (const std::vector<unsigned int> &permutation);

  std::vector<unsigned long long int>
  reverse_permutation (const std::vector<unsigned long long int> &permutation);

  std::vector<unsigned long long int>
  invert_permutation (const std::vector<unsigned long long int> &permutation);

  namespace System
  {

    double get_cpu_load ();

    struct MemoryStats
    {
      unsigned long int VmPeak;

      unsigned long int VmSize;

      unsigned long int VmHWM;

      unsigned long int VmRSS;
    };


    void get_memory_stats (MemoryStats &stats);


    std::string get_hostname ();


    std::string get_time ();

    std::string get_date ();

    void posix_memalign (void **memptr, size_t alignment, size_t size);

    bool job_supports_mpi () DEAL_II_DEPRECATED;
  }


#ifdef DEAL_II_WITH_TRILINOS

  namespace Trilinos
  {
    const Epetra_Comm &comm_world();

    const Epetra_Comm &comm_self();

    Epetra_Comm *
    duplicate_communicator (const Epetra_Comm &communicator);

    void
    destroy_communicator (Epetra_Comm &communicator);

    unsigned int get_n_mpi_processes (const Epetra_Comm &mpi_communicator);

    unsigned int get_this_mpi_process (const Epetra_Comm &mpi_communicator);

    Epetra_Map
    duplicate_map (const Epetra_BlockMap  &map,
                   const Epetra_Comm &comm);
  }

#endif


}


// --------------------- inline functions

namespace Utilities
{
  template <int N, typename T>
  inline
  T fixed_power (const T n)
  {
    Assert (N>0, ExcNotImplemented());
    switch (N)
      {
      case 1:
        return n;
      case 2:
        return n*n;
      case 3:
        return n*n*n;
      case 4:
        return n*n*n*n;
      default:
        T result = n;
        for (int d=1; d<N; ++d)
          result *= n;
        return result;
      }
  }



  template<typename Iterator, typename T>
  inline
  Iterator
  lower_bound (Iterator  first,
               Iterator  last,
               const T  &val)
  {
    return Utilities::lower_bound (first, last, val,
                                   std::less<T>());
  }



  template<typename Iterator, typename T, typename Comp>
  inline
  Iterator
  lower_bound (Iterator    first,
               Iterator    last,
               const T    &val,
               const Comp  comp)
  {
    // verify that the two iterators are properly ordered. since
    // we need operator- for the iterator type anyway, do the
    // test as follows, rather than via 'last >= first'
    Assert (last - first >= 0,
            ExcMessage ("The given iterators do not satisfy the proper ordering."));

    unsigned int len = static_cast<unsigned int>(last-first);

    if (len==0)
      return first;

    while (true)
      {
        // if length equals 8 or less,
        // then do a rolled out
        // search. use a switch without
        // breaks for that and roll-out
        // the loop somehow
        if (len < 8)
          {
            switch (len)
              {
              case 7:
                if (!comp(*first, val))
                  return first;
                ++first;
              case 6:
                if (!comp(*first, val))
                  return first;
                ++first;
              case 5:
                if (!comp(*first, val))
                  return first;
                ++first;
              case 4:
                if (!comp(*first, val))
                  return first;
                ++first;
              case 3:
                if (!comp(*first, val))
                  return first;
                ++first;
              case 2:
                if (!comp(*first, val))
                  return first;
                ++first;
              case 1:
                if (!comp(*first, val))
                  return first;
                return first+1;
              default:
                // indices seem
                // to not be
                // sorted
                // correctly!? or
                // did len
                // become==0
                // somehow? that
                // shouldn't have
                // happened
                Assert (false, ExcInternalError());
              }
          }



        const unsigned int half   = len >> 1;
        const Iterator     middle = first + half;

        // if the value is larger than
        // that pointed to by the
        // middle pointer, then the
        // insertion point must be
        // right of it
        if (comp(*middle, val))
          {
            first = middle + 1;
            len  -= half + 1;
          }
        else
          len = half;
      }
  }
}


DEAL_II_NAMESPACE_CLOSE

#endif