Utilities::System Namespace Reference
[Utility functions and classes]


Classes

class  MPI_InitFinalize

Functions

double get_cpu_load ()
std::string get_hostname ()
std::string get_time ()
bool job_supports_mpi ()
unsigned int get_n_mpi_processes (const MPI_Comm &mpi_communicator)
unsigned int get_this_mpi_process (const MPI_Comm &mpi_communicator)
MPI_Comm duplicate_communicator (const MPI_Comm &mpi_communicator)
bool program_uses_mpi ()

Detailed Description

A namespace for utility functions that probe system properties.


Function Documentation

double Utilities::System::get_cpu_load (  ) 

Return the CPU load as returned by "uptime". Note that the interpretation of this number depends on the actual number of processors in the machine. This is presently only implemented on Linux, using the /proc/loadavg pseudo-file, on other systems we simply return zero.

std::string Utilities::System::get_hostname (  ) 

Return the name of the host this process runs on.

std::string Utilities::System::get_time (  ) 

Return the present time as HH:MM:SS.

bool Utilities::System::job_supports_mpi (  ) 

Return whether (i) deal.II has been compiled to support MPI (for example by compiling with CXX=mpiCC) and if so whether (ii) MPI_Init() has been called (for example using the Utilities::System::MPI_InitFinalize class). In other words, the result indicates whether the current job is running under MPI.

unsigned int Utilities::System::get_n_mpi_processes ( const MPI_Comm &  mpi_communicator  ) 

Return the number of MPI processes there exist in the given communicator object. If this is a sequential job, it returns 1.

unsigned int Utilities::System::get_this_mpi_process ( const MPI_Comm &  mpi_communicator  ) 

Return the number of the present MPI process in the space of processes described by the given communicator. This will be a unique value for each process between zero and (less than) the number of all processes (given by get_n_mpi_processes()).

MPI_Comm Utilities::System::duplicate_communicator ( const MPI_Comm &  mpi_communicator  ) 

Given a communicator, generate a new communicator that contains the same set of processors but that has a different, unique identifier.

This functionality can be used to ensure that different objects, such as distributed matrices, each have unique communicators over which they can interact without interfering with each other.

When no longer needed, the communicator created here needs to be destroyed using MPI_Comm_free.

bool Utilities::System::program_uses_mpi (  ) 

Returns whether deal.II has been configured to use MPI and if so whether MPI has already been initialized using MPI_Init().


deal.II documentation generated on Mon Mar 15 23:09:26 2010 by doxygen 1.5.9