Dune::CollectiveCommunication< MPI_Comm > Class Reference

Specialization of CollectiveCommunication for MPI. More...

#include <dune/common/parallel/mpicollectivecommunication.hh>

Public Member Functions
	CollectiveCommunication (const MPI_Comm &c=MPI_COMM_WORLD)
	Instantiation using a MPI communicator.
int	rank () const
	Return rank, is between 0 and size()-1. More...
int	size () const
	Number of processes in set, is greater than 0. More...
template<typename T >
T	sum (T &in) const
	Compute the sum of the argument over all processes and return the result in every process. Assumes that T has an operator+. More...
template<typename T >
int	sum (T *inout, int len) const
	Compute the sum of the argument over all processes and return the result in every process. Assumes that T has an operator+. More...
template<typename T >
T	prod (T &in) const
	Compute the product of the argument over all processes and return the result in every process. Assumes that T has an operator*. More...
template<typename T >
int	prod (T *inout, int len) const
	Compute the product of the argument over all processes and return the result in every process. Assumes that T has an operator*. More...
template<typename T >
T	min (T &in) const
	Compute the minimum of the argument over all processes and return the result in every process. Assumes that T has an operator<. More...
template<typename T >
int	min (T *inout, int len) const
	Compute the minimum of the argument over all processes and return the result in every process. Assumes that T has an operator<. More...
template<typename T >
T	max (T &in) const
	Compute the maximum of the argument over all processes and return the result in every process. Assumes that T has an operator<. More...
template<typename T >
int	max (T *inout, int len) const
	Compute the maximum of the argument over all processes and return the result in every process. Assumes that T has an operator<. More...
int	barrier () const
	Wait until all processes have arrived at this point in the program. More...
template<typename T >
int	broadcast (T *inout, int len, int root) const
	Distribute an array from the process with rank root to all other processes. More...
template<typename T >
int	gather (T *in, T *out, int len, int root) const
	Gather arrays on root task. More...
template<typename T >
int	gatherv (T *in, int sendlen, T *out, int *recvlen, int *displ, int root) const
	Gather arrays of variable size on root task. More...
template<typename T >
int	scatter (T *send, T *recv, int len, int root) const
	Scatter array from a root to all other task. More...
template<typename T >
int	scatterv (T *send, int *sendlen, int *displ, T *recv, int recvlen, int root) const
	Scatter arrays of variable length from a root to all other tasks. More...
template<typename T , typename T1 >
int	allgather (T *sbuf, int count, T1 *rbuf) const
	Gathers data from all tasks and distribute it to all. More...
template<typename T >
int	allgatherv (T *in, int sendlen, T *out, int *recvlen, int *displ) const
	Gathers data of variable length from all tasks and distribute it to all. More...
template<typename BinaryFunction , typename Type >
int	allreduce (Type *inout, int len) const
	Compute something over all processes for each component of an array and return the result in every process. More...
template<typename BinaryFunction , typename Type >
int	allreduce (Type *in, Type *out, int len) const
	Compute something over all processes for each component of an array and return the result in every process. More...

Detailed Description

Specialization of CollectiveCommunication for MPI.

Member Function Documentation

allgather()

template<typename T , typename T1 >

int Dune::CollectiveCommunication< MPI_Comm >::allgather ( T *  sbuf, int  count, T1 *  rbuf  ) const

inline

Gathers data from all tasks and distribute it to all.

The block of data sent from the jth process is received by every process and placed in the jth block of the buffer recvbuf.

Parameters

[in]	sbuf	The buffer with the data to send. Has to be the same for each task.
[in]	count	The number of elements to send by any process.
[out]	rbuf	The receive buffer for the data. Has to be of size notasks*count, with notasks being the number of tasks in the communicator.

Returns

MPI_SUCCESS (==0) if successful, an MPI error code otherwise

allgatherv()

template<typename T >

int Dune::CollectiveCommunication< MPI_Comm >::allgatherv ( T *  in, int  sendlen, T *  out, int *  recvlen, int *  displ  ) const

inline

Gathers data of variable length from all tasks and distribute it to all.

The block of data sent from the jth process is received by every process and placed in the jth block of the buffer out.

Parameters

[in]	in	The send buffer with the data to send.
[in]	sendlen	The number of elements to send on each task.
[out]	out	The buffer to store the received data in.
[in]	recvlen	An array with size equal to the number of processes containing the number of elements to recieve from process i at position i, i.e. the number that is passed as sendlen argument to this function in process i.
[in]	displ	An array with size equal to the number of processes. Data recieved from process i will be written starting at out+displ[i].

Returns

MPI_SUCCESS (==0) if successful, an MPI error code otherwise

allreduce() [1/2]

template<typename BinaryFunction , typename Type >

int Dune::CollectiveCommunication< MPI_Comm >::allreduce ( Type *  in, Type *  out, int  len  ) const

inline

Compute something over all processes for each component of an array and return the result in every process.

The template parameter BinaryFunction is the type of the binary function to use for the computation

Parameters

in	The array to compute on.
out	The array to store the results in.
len	The number of components in the array

Returns

MPI_SUCCESS (==0) if successful, an MPI error code otherwise

allreduce() [2/2]

template<typename BinaryFunction , typename Type >

int Dune::CollectiveCommunication< MPI_Comm >::allreduce ( Type *  inout, int  len  ) const

inline

Compute something over all processes for each component of an array and return the result in every process.

The template parameter BinaryFunction is the type of the binary function to use for the computation

Parameters

inout	The array to compute on.
len	The number of components in the array

Returns

MPI_SUCCESS (==0) if successful, an MPI error code otherwise

barrier()

int Dune::CollectiveCommunication< MPI_Comm >::barrier ( ) const

inline

Wait until all processes have arrived at this point in the program.

Returns

MPI_SUCCESS (==0) if successful, an MPI error code otherwise

Referenced by Dune::graphRepartition().

broadcast()

template<typename T >

int Dune::CollectiveCommunication< MPI_Comm >::broadcast ( T *  inout, int  len, int  root  ) const

inline

Distribute an array from the process with rank root to all other processes.

Returns

MPI_SUCCESS (==0) if successful, an MPI error code otherwise

gather()

template<typename T >

int Dune::CollectiveCommunication< MPI_Comm >::gather ( T *  in, T *  out, int  len, int  root  ) const

inline

Gather arrays on root task.

Each process sends its in array of length len to the root process (including the root itself). In the root process these arrays are stored in rank order in the out array which must have size len * number of processes.

Parameters

[in]	in	The send buffer with the data to send.
[out]	out	The buffer to store the received data in. Might have length zero on non-root tasks.
[in]	len	The number of elements to send on each task.
[in]	root	The root task that gathers the data.

Returns

MPI_SUCCESS (==0) if successful, an MPI error code otherwise

Note

out must have space for P*len elements

gatherv()

template<typename T >

int Dune::CollectiveCommunication< MPI_Comm >::gatherv ( T *  in, int  sendlen, T *  out, int *  recvlen, int *  displ, int  root  ) const

inline

Gather arrays of variable size on root task.

Each process sends its in array of length sendlen to the root process (including the root itself). In the root process these arrays are stored in rank order in the out array.

Parameters

[in]	in	The send buffer with the data to be sent
[in]	sendlen	The number of elements to send on each task
[out]	out	The buffer to store the received data in. May have length zero on non-root tasks.
[in]	recvlen	An array with size equal to the number of processes containing the number of elements to receive from process i at position i, i.e. the number that is passed as sendlen argument to this function in process i. May have length zero on non-root tasks.
[out]	displ	An array with size equal to the number of processes. Data received from process i will be written starting at out+displ[i] on the root process. May have length zero on non-root tasks.
[in]	root	The root task that gathers the data.

Returns

MPI_SUCCESS (==0) if successful, an MPI error code otherwise

max() [1/2]

template<typename T >

T Dune::CollectiveCommunication< MPI_Comm >::max ( T &  in ) const

inline

Compute the maximum of the argument over all processes and return the result in every process. Assumes that T has an operator<.

Referenced by Dune::YaspGrid< dim, Coordinates >::preAdapt().

max() [2/2]

template<typename T >

int Dune::CollectiveCommunication< MPI_Comm >::max ( T *  inout, int  len  ) const

inline

Compute the maximum of the argument over all processes and return the result in every process. Assumes that T has an operator<.

min() [1/2]

template<typename T >

T Dune::CollectiveCommunication< MPI_Comm >::min ( T &  in ) const

inline

Compute the minimum of the argument over all processes and return the result in every process. Assumes that T has an operator<.

min() [2/2]

template<typename T >

int Dune::CollectiveCommunication< MPI_Comm >::min ( T *  inout, int  len  ) const

inline

Compute the minimum of the argument over all processes and return the result in every process. Assumes that T has an operator<.

prod() [1/2]

template<typename T >

T Dune::CollectiveCommunication< MPI_Comm >::prod ( T &  in ) const

inline

Compute the product of the argument over all processes and return the result in every process. Assumes that T has an operator*.

prod() [2/2]

template<typename T >

int Dune::CollectiveCommunication< MPI_Comm >::prod ( T *  inout, int  len  ) const

inline

Compute the product of the argument over all processes and return the result in every process. Assumes that T has an operator*.

rank()

int Dune::CollectiveCommunication< MPI_Comm >::rank ( ) const

inline

Return rank, is between 0 and size()-1.

Referenced by Dune::BackupRestoreFacility< Dune::YaspGrid< dim, Coordinates > >::backup(), Dune::BackupRestoreFacility< YaspGrid< dim, TensorProductCoordinates< ctype, dim > > >::backup(), Dune::graphRepartition(), and Dune::storeMatrixMarket().

scatter()

template<typename T >

int Dune::CollectiveCommunication< MPI_Comm >::scatter ( T *  send, T *  recv, int  len, int  root  ) const

inline

Scatter array from a root to all other task.

The root process sends the elements with index from k*len to (k+1)*len-1 in its array to task k, which stores it at index 0 to len-1.

Parameters

[in]	send	The array to scatter. Might have length zero on non-root tasks.
[out]	recv	The buffer to store the received data in. Upon completion of the method each task will have same data stored there as the one in send buffer of the root task before.
[in]	len	The number of elements in the recv buffer.
[in]	root	The root task that gathers the data.

Returns

MPI_SUCCESS (==0) if successful, an MPI error code otherwise

Note

out must have space for P*len elements

scatterv()

template<typename T >

int Dune::CollectiveCommunication< MPI_Comm >::scatterv ( T *  send, int *  sendlen, int *  displ, T *  recv, int  recvlen, int  root  ) const

inline

Scatter arrays of variable length from a root to all other tasks.

The root process sends the elements with index from send+displ[k] to send+displ[k]-1 in its array to task k, which stores it at index 0 to recvlen-1.

Parameters

[in]	send	The array to scatter. May have length zero on non-root tasks.
[in]	sendlen	An array with size equal to the number of processes containing the number of elements to scatter to process i at position i, i.e. the number that is passed as recvlen argument to this function in process i.
[in]	displ	An array with size equal to the number of processes. Data scattered to process i will be read starting at send+displ[i] on root the process.
[out]	recv	The buffer to store the received data in. Upon completion of the method each task will have the same data stored there as the one in send buffer of the root task before.
[in]	recvlen	The number of elements in the recv buffer.
[in]	root	The root task that gathers the data.

Returns

MPI_SUCCESS (==0) if successful, an MPI error code otherwise

size()

int Dune::CollectiveCommunication< MPI_Comm >::size ( ) const

inline

Number of processes in set, is greater than 0.

Referenced by Dune::graphRepartition().

sum() [1/2]

template<typename T >

T Dune::CollectiveCommunication< MPI_Comm >::sum ( T &  in ) const

inline

Compute the sum of the argument over all processes and return the result in every process. Assumes that T has an operator+.

Referenced by Dune::OwnerOverlapCopyCommunication< GlobalIdType, LocalIdType >::dot(), and Dune::OwnerOverlapCopyCommunication< GlobalIdType, LocalIdType >::norm().

sum() [2/2]

template<typename T >

int Dune::CollectiveCommunication< MPI_Comm >::sum ( T *  inout, int  len  ) const

inline

Compute the sum of the argument over all processes and return the result in every process. Assumes that T has an operator+.

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The documentation for this class was generated from the following file:

• dune/common/parallel/mpicollectivecommunication.hh