A namespace for utility functions that abstract certain operations using the Message Passing Interface (MPI) or provide fallback operations in case deal.II is configured not to use MPI at all.
MPI_Comm Utilities::MPI::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
.
Definition at line 113 of file mpi.cc.
template<typename T , unsigned int N>
void Utilities::MPI::sum 
( 
const T(&) 
values[N], 


const MPI_Comm & 
mpi_communicator, 


T(&) 
sums[N] 

) 
 

inline 
Like the previous function, but take the sums over the elements of an array of length N. In other words, the ith element of the results array is the sum over the ith entries of the input arrays from each processor.
Input and output arrays may be the same.
Definition at line 616 of file mpi.h.
template<typename T >
void Utilities::MPI::sum 
( 
const std::vector< T > & 
values, 


const MPI_Comm & 
mpi_communicator, 


std::vector< T > & 
sums 

) 
 

inline 
Like the previous function, but take the sums over the elements of a std::vector. In other words, the ith element of the results array is the sum over the ith entries of the input arrays from each processor.
Input and output vectors may be the same.
Definition at line 626 of file mpi.h.
template<typename T , unsigned int N>
void Utilities::MPI::max 
( 
const T(&) 
values[N], 


const MPI_Comm & 
mpi_communicator, 


T(&) 
maxima[N] 

) 
 

inline 
Like the previous function, but take the maxima over the elements of an array of length N. In other words, the ith element of the results array is the maximum of the ith entries of the input arrays from each processor.
Input and output arrays may be the same.
Definition at line 698 of file mpi.h.
template<typename T >
void Utilities::MPI::max 
( 
const std::vector< T > & 
values, 


const MPI_Comm & 
mpi_communicator, 


std::vector< T > & 
maxima 

) 
 

inline 
Like the previous function, but take the maximum over the elements of a std::vector. In other words, the ith element of the results array is the maximum over the ith entries of the input arrays from each processor.
Input and output vectors may be the same.
Definition at line 708 of file mpi.h.
template<typename T , unsigned int N>
void Utilities::MPI::min 
( 
const T(&) 
values[N], 


const MPI_Comm & 
mpi_communicator, 


T(&) 
minima[N] 

) 
 

inline 
Like the previous function, but take the minima over the elements of an array of length N. In other words, the ith element of the results array is the minimum of the ith entries of the input arrays from each processor.
Input and output arrays may be the same.
Definition at line 727 of file mpi.h.
template<typename T >
void Utilities::MPI::min 
( 
const std::vector< T > & 
values, 


const MPI_Comm & 
mpi_communicator, 


std::vector< T > & 
minima 

) 
 

inline 
Like the previous function, but take the minimum over the elements of a std::vector. In other words, the ith element of the results array is the minimum over the ith entries of the input arrays from each processor.
Input and output vectors may be the same.
Definition at line 737 of file mpi.h.
MinMaxAvg Utilities::MPI::min_max_avg 
( 
const double 
my_value, 


const MPI_Comm & 
mpi_communicator 

) 
 
Returns sum, average, minimum, maximum, processor id of minimum and maximum as a collective operation of on the given MPI communicator mpi_communicator
. Each processor's value is given in my_value
and the result will be returned. The result is available on all machines.
 Note
 Sometimes, not all processors need a result and in that case one would call the
MPI_Reduce
function instead of the MPI_Allreduce
function. The latter is at most twice as expensive, so if you are concerned about performance, it may be worthwhile investigating whether your algorithm indeed needs the result everywhere.
Definition at line 235 of file mpi.cc.