Nektar::LibUtilities::CommMpi Class Reference

A global linear system. More...

#include <CommMpi.h>

Inheritance diagram for Nektar::LibUtilities::CommMpi:

Collaboration diagram for Nektar::LibUtilities::CommMpi:

Public Member Functions
	CommMpi (int narg, char *arg[])
virtual	~CommMpi ()
MPI_Comm	GetComm ()
Public Member Functions inherited from Nektar::LibUtilities::Comm
	Comm (int narg, char *arg[])
virtual	~Comm ()
void	Finalise ()
int	GetSize ()
	Returns number of processes. More...
int	GetRank ()
const std::string &	GetType () const
void	Block ()
	Block execution until all processes reach this point. More...
NekDouble	Wtime ()
	Return the time in seconds. More...
template<class T >
void	Send (int pProc, T &pData)
template<class T >
void	Recv (int pProc, T &pData)
template<class T >
void	SendRecv (int pSendProc, T &pSendData, int pRecvProc, T &pRecvData)
template<class T >
void	SendRecvReplace (int pSendProc, int pRecvProc, T &pData)
template<class T >
void	AllReduce (T &pData, enum ReduceOperator pOp)
template<class T >
void	AlltoAll (T &pSendData, T &pRecvData)
template<class T >
void	AlltoAllv (Array< OneD, T > &pSendData, Array< OneD, int > &pSendDataSizeMap, Array< OneD, int > &pSendDataOffsetMap, Array< OneD, T > &pRecvData, Array< OneD, int > &pRecvDataSizeMap, Array< OneD, int > &pRecvDataOffsetMap)
template<class T >
void	Bcast (T &data, int rootProc)
template<class T >
void	Exscan (T &pData, const enum ReduceOperator pOp, T &ans)
template<class T >
T	Gather (const int rootProc, T &val)
template<class T >
T	Scatter (const int rootProc, T &pData)
CommSharedPtr	CommCreateIf (int flag)
	If the flag is non-zero create a new communicator. More...
void	SplitComm (int pRows, int pColumns)
	Splits this communicator into a grid of size pRows*pColumns and creates row and column communicators. By default the communicator is a single row. More...
CommSharedPtr	GetRowComm ()
	Retrieve the row communicator to which this process belongs. More...
CommSharedPtr	GetColumnComm ()
	Retrieve the column communicator to which this process belongs. More...
bool	TreatAsRankZero (void)
bool	RemoveExistingFiles (void)

Static Public Member Functions
static CommSharedPtr	create (int narg, char *arg[])
	Creates an instance of this class. More...

Static Public Attributes
static std::string	className
	Name of class. More...

Protected Member Functions
virtual void	v_Finalise ()
virtual int	v_GetRank ()
virtual void	v_Block ()
virtual double	v_Wtime ()
virtual bool	v_TreatAsRankZero (void)
virtual void	v_Send (void *buf, int count, CommDataType dt, int dest)
virtual void	v_Recv (void *buf, int count, CommDataType dt, int source)
virtual void	v_SendRecv (void *sendbuf, int sendcount, CommDataType sendtype, int dest, void *recvbuf, int recvcount, CommDataType recvtype, int source)
virtual void	v_SendRecvReplace (void *buf, int count, CommDataType dt, int pSendProc, int pRecvProc)
virtual void	v_AllReduce (void *buf, int count, CommDataType dt, enum ReduceOperator pOp)
virtual void	v_AlltoAll (void *sendbuf, int sendcount, CommDataType sendtype, void *recvbuf, int recvcount, CommDataType recvtype)
virtual void	v_AlltoAllv (void *sendbuf, int sendcounts[], int sensdispls[], CommDataType sendtype, void *recvbuf, int recvcounts[], int rdispls[], CommDataType recvtype)
virtual void	v_Bcast (void *buffer, int count, CommDataType dt, int root)
virtual void	v_Exscan (Array< OneD, unsigned long long > &pData, const enum ReduceOperator pOp, Array< OneD, unsigned long long > &ans)
virtual void	v_Gather (void *sendbuf, int sendcount, CommDataType sendtype, void *recvbuf, int recvcount, CommDataType recvtype, int root)
virtual void	v_Scatter (void *sendbuf, int sendcount, CommDataType sendtype, void *recvbuf, int recvcount, CommDataType recvtype, int root)
virtual void	v_SplitComm (int pRows, int pColumns)
virtual CommSharedPtr	v_CommCreateIf (int flag)
Protected Member Functions inherited from Nektar::LibUtilities::Comm
	Comm ()
virtual bool	v_RemoveExistingFiles (void)

Private Member Functions
	CommMpi (MPI_Comm pComm)

Private Attributes
MPI_Comm	m_comm
int	m_rank

Additional Inherited Members
Protected Attributes inherited from Nektar::LibUtilities::Comm
int	m_size
	Number of processes. More...
std::string	m_type
	Type of communication. More...
CommSharedPtr	m_commRow
	Row communicator. More...
CommSharedPtr	m_commColumn
	Column communicator. More...

Detailed Description

A global linear system.

Definition at line 61 of file CommMpi.h.

Constructor & Destructor Documentation

Nektar::LibUtilities::CommMpi::CommMpi	(	int	narg,
		char *	arg[]
	)

Definition at line 53 of file CommMpi.cpp.

References ASSERTL0, m_comm, m_rank, Nektar::LibUtilities::Comm::m_size, and Nektar::LibUtilities::Comm::m_type.

Referenced by v_CommCreateIf(), and v_SplitComm().

                                      : Comm(narg, arg)
{
    int init = 0;
    MPI_Initialized(&init);
    ASSERTL0(!init, "MPI has already been initialised.");

    int retval = MPI_Init(&narg, &arg);
    if (retval != MPI_SUCCESS)
    {
        ASSERTL0(false, "Failed to initialise MPI");
    }

    m_comm = MPI_COMM_WORLD;
    MPI_Comm_size(m_comm, &m_size);
    MPI_Comm_rank(m_comm, &m_rank);

#ifdef NEKTAR_USING_PETSC
    PetscInitializeNoArguments();
#endif

    m_type = "Parallel MPI";
}

Nektar::LibUtilities::CommMpi::~CommMpi ( )

virtual

Definition at line 91 of file CommMpi.cpp.

{
}

Nektar::LibUtilities::CommMpi::CommMpi ( MPI_Comm  pComm )

private

Definition at line 79 of file CommMpi.cpp.

References m_comm, m_rank, Nektar::LibUtilities::Comm::m_size, and Nektar::LibUtilities::Comm::m_type.

                               : Comm()
{
    m_comm = pComm;
    MPI_Comm_size(m_comm, &m_size);
    MPI_Comm_rank(m_comm, &m_rank);

    m_type = "Parallel MPI";
}

Member Function Documentation

static CommSharedPtr Nektar::LibUtilities::CommMpi::create ( int  narg, char *  arg[]  )

inlinestatic

Creates an instance of this class.

Definition at line 65 of file CommMpi.h.

References Nektar::MemoryManager< DataType >::AllocateSharedPtr().

    {
        return MemoryManager<CommMpi>::AllocateSharedPtr(narg, arg);
    }

MPI_Comm Nektar::LibUtilities::CommMpi::GetComm

(

)

Definition at line 98 of file CommMpi.cpp.

References m_comm.

Referenced by Nektar::MultiRegions::GlobalLinSysPETSc::GlobalLinSysPETSc().

{
    return m_comm;
}

void Nektar::LibUtilities::CommMpi::v_AllReduce ( void *  buf, int  count, CommDataType  dt, enum ReduceOperator  pOp  )

protectedvirtual

Implements Nektar::LibUtilities::Comm.

Definition at line 216 of file CommMpi.cpp.

References ASSERTL0, Nektar::LibUtilities::Comm::GetSize(), m_comm, Nektar::LibUtilities::ReduceMax, Nektar::LibUtilities::ReduceMin, and Nektar::LibUtilities::ReduceSum.

{
    if (GetSize() == 1)
    {
        return;
    }

    MPI_Op vOp;
    switch (pOp)
    {
        case ReduceMax:
            vOp = MPI_MAX;
            break;
        case ReduceMin:
            vOp = MPI_MIN;
            break;
        case ReduceSum:
        default:
            vOp = MPI_SUM;
            break;
    }
    int retval = MPI_Allreduce(MPI_IN_PLACE, buf, count, dt, vOp, m_comm);

    ASSERTL0(retval == MPI_SUCCESS, "MPI error performing All-reduce.");
}

void Nektar::LibUtilities::CommMpi::v_AlltoAll ( void *  sendbuf, int  sendcount, CommDataType  sendtype, void *  recvbuf, int  recvcount, CommDataType  recvtype  )

protectedvirtual

Implements Nektar::LibUtilities::Comm.

Definition at line 246 of file CommMpi.cpp.

References ASSERTL0, and m_comm.

{
    int retval = MPI_Alltoall(sendbuf, sendcount, sendtype, recvbuf, recvcount,
                              recvtype, m_comm);

    ASSERTL0(retval == MPI_SUCCESS, "MPI error performing All-to-All.");
}

void Nektar::LibUtilities::CommMpi::v_AlltoAllv ( void *  sendbuf, int  sendcounts[], int  sensdispls[], CommDataType  sendtype, void *  recvbuf, int  recvcounts[], int  rdispls[], CommDataType  recvtype  )

protectedvirtual

Implements Nektar::LibUtilities::Comm.

Definition at line 258 of file CommMpi.cpp.

References ASSERTL0, and m_comm.

{
    int retval = MPI_Alltoallv(sendbuf, sendcounts, sdispls, sendtype, recvbuf,
                               recvcounts, rdispls, recvtype, m_comm);

    ASSERTL0(retval == MPI_SUCCESS, "MPI error performing All-to-All-v.");
}

void Nektar::LibUtilities::CommMpi::v_Bcast ( void *  buffer, int  count, CommDataType  dt, int  root  )

protectedvirtual

Implements Nektar::LibUtilities::Comm.

Definition at line 269 of file CommMpi.cpp.

References ASSERTL0, and m_comm.

{
    int retval = MPI_Bcast(buffer, count, dt, root, m_comm);
    ASSERTL0(retval == MPI_SUCCESS, "MPI error performing Bcast-v.");
}

void Nektar::LibUtilities::CommMpi::v_Block ( )

protectedvirtual

Implements Nektar::LibUtilities::Comm.

Definition at line 146 of file CommMpi.cpp.

References m_comm.

{
    MPI_Barrier(m_comm);
}

CommSharedPtr Nektar::LibUtilities::CommMpi::v_CommCreateIf ( int  flag )

protectedvirtual

Create a new communicator if the flag is non-zero.

Implements Nektar::LibUtilities::Comm.

Definition at line 354 of file CommMpi.cpp.

References CommMpi(), and m_comm.

{
    MPI_Comm newComm;
    // color == MPI_UNDEF => not in the new communicator
    // key == 0 on all => use rank to order them. OpenMPI, at least,
    // implies this is faster than ordering them ourselves.
    MPI_Comm_split(m_comm, flag ? 0 : MPI_UNDEFINED, 0, &newComm);

    if (flag == 0)
    {
        // flag == 0 => get back MPI_COMM_NULL, return a null ptr instead.
        return boost::shared_ptr<Comm>();
    }
    else
    {
        // Return a real communicator
        return boost::shared_ptr<Comm>(new CommMpi(newComm));
    }
}

void Nektar::LibUtilities::CommMpi::v_Exscan ( Array< OneD, unsigned long long > &  pData, const enum ReduceOperator  pOp, Array< OneD, unsigned long long > &  ans  )

protectedvirtual

Implements Nektar::LibUtilities::Comm.

Definition at line 275 of file CommMpi.cpp.

References ASSERTL0, m_comm, Nektar::LibUtilities::MPI_UNSIGNED_LONG_LONG, Nektar::LibUtilities::ReduceMax, Nektar::LibUtilities::ReduceMin, and Nektar::LibUtilities::ReduceSum.

{
    int n = pData.num_elements();
    ASSERTL0(n == ans.num_elements(), "Array sizes differ in Exscan");

    MPI_Op vOp;
    switch (pOp)
    {
        case ReduceMax:
            vOp = MPI_MAX;
            break;
        case ReduceMin:
            vOp = MPI_MIN;
            break;
        case ReduceSum:
        default:
            vOp = MPI_SUM;
            break;
    }

    int retval = MPI_Exscan(pData.get(), ans.get(), n, MPI_UNSIGNED_LONG_LONG,
                            vOp, m_comm);
    ASSERTL0(retval == MPI_SUCCESS, "MPI error performing Exscan-v.");
}

void Nektar::LibUtilities::CommMpi::v_Finalise ( )

protectedvirtual

Implements Nektar::LibUtilities::Comm.

Definition at line 106 of file CommMpi.cpp.

{
#ifdef NEKTAR_USING_PETSC
    PetscFinalize();
#endif
    int flag;
    MPI_Finalized(&flag);
    if (!flag)
    {
        MPI_Finalize();
    }
}

void Nektar::LibUtilities::CommMpi::v_Gather ( void *  sendbuf, int  sendcount, CommDataType  sendtype, void *  recvbuf, int  recvcount, CommDataType  recvtype, int  root  )

protectedvirtual

Implements Nektar::LibUtilities::Comm.

Definition at line 302 of file CommMpi.cpp.

References ASSERTL0, and m_comm.

{
    int retval = MPI_Gather(sendbuf, sendcount, sendtype, recvbuf, recvcount,
                            recvtype, root, m_comm);

    ASSERTL0(retval == MPI_SUCCESS, "MPI error performing Gather.");
}

int Nektar::LibUtilities::CommMpi::v_GetRank ( void  )

protectedvirtual

Implements Nektar::LibUtilities::Comm.

Definition at line 122 of file CommMpi.cpp.

References m_rank.

{
    return m_rank;
}

void Nektar::LibUtilities::CommMpi::v_Recv ( void *  buf, int  count, CommDataType  dt, int  source  )

protectedvirtual

Implements Nektar::LibUtilities::Comm.

Definition at line 177 of file CommMpi.cpp.

References m_comm.

{
    MPI_Recv(buf, count, dt, source, 0, m_comm, MPI_STATUS_IGNORE);
    // ASSERTL0(status.MPI_ERROR == MPI_SUCCESS,
    //         "MPI error receiving data.");
}

void Nektar::LibUtilities::CommMpi::v_Scatter ( void *  sendbuf, int  sendcount, CommDataType  sendtype, void *  recvbuf, int  recvcount, CommDataType  recvtype, int  root  )

protectedvirtual

Implements Nektar::LibUtilities::Comm.

Definition at line 312 of file CommMpi.cpp.

References ASSERTL0, and m_comm.

{
    int retval = MPI_Scatter(sendbuf, sendcount, sendtype, recvbuf, recvcount,
                             recvtype, root, m_comm);
    ASSERTL0(retval == MPI_SUCCESS, "MPI error performing Scatter.");
}

void Nektar::LibUtilities::CommMpi::v_Send ( void *  buf, int  count, CommDataType  dt, int  dest  )

protectedvirtual

Implements Nektar::LibUtilities::Comm.

Definition at line 162 of file CommMpi.cpp.

References m_comm, and MPISYNC.

{
    if (MPISYNC)
    {
        MPI_Ssend(buf, count, dt, dest, 0, m_comm);
    }
    else
    {
        MPI_Send(buf, count, dt, dest, 0, m_comm);
    }
}

void Nektar::LibUtilities::CommMpi::v_SendRecv ( void *  sendbuf, int  sendcount, CommDataType  sendtype, int  dest, void *  recvbuf, int  recvcount, CommDataType  recvtype, int  source  )

protectedvirtual

Implements Nektar::LibUtilities::Comm.

Definition at line 187 of file CommMpi.cpp.

References ASSERTL0, and m_comm.

{
    MPI_Status status;
    int retval = MPI_Sendrecv(sendbuf, sendcount, sendtype, dest, 0, recvbuf,
                              recvcount, recvtype, source, 0, m_comm, &status);

    ASSERTL0(retval == MPI_SUCCESS,
             "MPI error performing send-receive of data.");
}

void Nektar::LibUtilities::CommMpi::v_SendRecvReplace ( void *  buf, int  count, CommDataType  dt, int  pSendProc, int  pRecvProc  )

protectedvirtual

Implements Nektar::LibUtilities::Comm.

Definition at line 202 of file CommMpi.cpp.

References ASSERTL0, and m_comm.

{
    MPI_Status status;
    int retval = MPI_Sendrecv_replace(buf, count, dt, pRecvProc, 0, pSendProc,
                                      0, m_comm, &status);

    ASSERTL0(retval == MPI_SUCCESS,
             "MPI error performing Send-Receive-Replace of data.");
}

void Nektar::LibUtilities::CommMpi::v_SplitComm ( int  pRows, int  pColumns  )

protectedvirtual

Processes are considered as a grid of size pRows*pColumns. Comm objects are created corresponding to the rows and columns of this grid. The row and column to which this process belongs is stored in m_commRow and m_commColumn.

Implements Nektar::LibUtilities::Comm.

Definition at line 327 of file CommMpi.cpp.

References ASSERTL0, CommMpi(), m_comm, Nektar::LibUtilities::Comm::m_commColumn, Nektar::LibUtilities::Comm::m_commRow, m_rank, and Nektar::LibUtilities::Comm::m_size.

{
    ASSERTL0(pRows * pColumns == m_size,
             "Rows/Columns do not match comm size.");

    MPI_Comm newComm;

    // Compute row and column in grid.
    int myCol = m_rank % pColumns;
    int myRow = (m_rank - myCol) / pColumns;

    // Split Comm into rows - all processes with same myRow are put in
    // the same communicator. The rank within this communicator is the
    // column index.
    MPI_Comm_split(m_comm, myRow, myCol, &newComm);
    m_commRow = boost::shared_ptr<Comm>(new CommMpi(newComm));

    // Split Comm into columns - all processes with same myCol are put
    // in the same communicator. The rank within this communicator is
    // the row index.
    MPI_Comm_split(m_comm, myCol, myRow, &newComm);
    m_commColumn = boost::shared_ptr<Comm>(new CommMpi(newComm));
}

bool Nektar::LibUtilities::CommMpi::v_TreatAsRankZero ( void  )

protectedvirtual

Implements Nektar::LibUtilities::Comm.

Definition at line 130 of file CommMpi.cpp.

References m_rank.

{
    if (m_rank == 0)
    {
        return true;
    }
    else
    {
        return false;
    }
    return true;
}

double Nektar::LibUtilities::CommMpi::v_Wtime ( )

protectedvirtual

Implements Nektar::LibUtilities::Comm.

Definition at line 154 of file CommMpi.cpp.

{
    return MPI_Wtime();
}

Member Data Documentation

std::string Nektar::LibUtilities::CommMpi::className

static

Initial value:

= GetCommFactory().RegisterCreatorFunction(
    "ParallelMPI", CommMpi::create, "Parallel communication using MPI.")

Name of class.

Definition at line 71 of file CommMpi.h.

MPI_Comm Nektar::LibUtilities::CommMpi::m_comm

private

Definition at line 116 of file CommMpi.h.

Referenced by CommMpi(), GetComm(), v_AllReduce(), v_AlltoAll(), v_AlltoAllv(), v_Bcast(), v_Block(), v_CommCreateIf(), v_Exscan(), v_Gather(), v_Recv(), v_Scatter(), v_Send(), v_SendRecv(), v_SendRecvReplace(), and v_SplitComm().

int Nektar::LibUtilities::CommMpi::m_rank

private

Definition at line 117 of file CommMpi.h.

Referenced by CommMpi(), v_GetRank(), v_SplitComm(), and v_TreatAsRankZero().