C++ DistMatrix::LockedLocalBuffer方法代码示例

/*
 * Distributes A in such a way that
 *   Layer 0 <- A(:, 0:(n/h - 1))
 *   Layer 1 <- A(:, (n/h):(2n/h - 1))
 *     .
 *     .
 *     .
 *   Layer h-1 <- A(:, ((h-1)n/h):n)
 */
void DistributeCols
( const mpi::Comm& depthComm,
  const DistMatrix<double,MC,MR>& A, 
        DistMatrix<double,MC,MR>& B )
{
    const Grid& meshGrid = A.Grid();
    const int meshSize = meshGrid.Size();
    const int depthSize = mpi::CommSize( depthComm );
    const int depthRank = mpi::CommRank( depthComm );

    const int sendCount = A.LocalHeight()*A.LocalWidth();
    const int recvCount = sendCount / depthSize;

    // For now, we will make B as large as A...
    // TODO: NOT DO THIS
    if( A.LocalHeight() != A.LocalLDim() )
        throw std::logic_error("Local height did not match local ldim");
    B.Empty();
    B.AlignWith( A );
    Zeros( A.Height(), A.Width(), B );

    // Scatter
    const int localColOffset = (A.LocalWidth()/depthSize)*depthRank;
    mpi::Scatter
    ( A.LockedLocalBuffer(), recvCount, 
      B.LocalBuffer(0,localColOffset), recvCount, 0, depthComm );
}

inline void HermitianSVD
( UpperOrLower uplo, 
  DistMatrix<F>& A, DistMatrix<typename Base<F>::type,VR,STAR>& s, 
  DistMatrix<F>& U, DistMatrix<F>& V )
{
#ifndef RELEASE
    PushCallStack("HermitianSVD");
#endif
    typedef typename Base<F>::type R;

    // Grab an eigenvalue decomposition of A
    HermitianEig( uplo, A, s, V ); 
    
    // Redistribute the singular values into an [MR,* ] distribution
    const Grid& grid = A.Grid();
    DistMatrix<R,MR,STAR> s_MR_STAR( grid );
    s_MR_STAR.AlignWith( V );
    s_MR_STAR = s;

    // Set the singular values to the absolute value of the eigenvalues
    const int numLocalVals = s.LocalHeight();
    for( int iLocal=0; iLocal<numLocalVals; ++iLocal )
    {
        const R sigma = s.GetLocal(iLocal,0);
        s.SetLocal(iLocal,0,Abs(sigma));
    }

    // Copy V into U (flipping the sign as necessary)
    U.AlignWith( V );
    U.ResizeTo( V.Height(), V.Width() );
    const int localHeight = V.LocalHeight();
    const int localWidth = V.LocalWidth();
    for( int jLocal=0; jLocal<localWidth; ++jLocal )
    {
        const R sigma = s_MR_STAR.GetLocal( jLocal, 0 );
        F* UCol = U.LocalBuffer( 0, jLocal );
        const F* VCol = V.LockedLocalBuffer( 0, jLocal );
        if( sigma >= 0 )
            for( int iLocal=0; iLocal<localHeight; ++iLocal )
                UCol[iLocal] = VCol[iLocal];
        else
            for( int iLocal=0; iLocal<localHeight; ++iLocal )
                UCol[iLocal] = -VCol[iLocal];
    }
#ifndef RELEASE
    PopCallStack();
#endif
}

inline const DistMatrix<T,MD,STAR,Int>&
DistMatrix<T,MD,STAR,Int>::operator=( const DistMatrix<T,STAR,STAR,Int>& A )
{
#ifndef RELEASE
    PushCallStack("[MD,* ] = [* ,* ]");
    this->AssertNotLockedView();
    this->AssertSameGrid( A );
    if( this->Viewing() )
        this->AssertSameSize( A );
#endif
    if( !this->Viewing() )
        this->ResizeTo( A.Height(), A.Width() );

    if( this->Participating() )
    {
        const Int lcm = this->grid_->LCM();
        const Int colShift = this->ColShift();

        const Int width = this->Width();
        const Int localHeight = this->LocalHeight();

        const T* ALocalBuffer = A.LockedLocalBuffer();
        const Int ALDim = A.LocalLDim();
        T* thisLocalBuffer = this->LocalBuffer();
        const Int thisLDim = this->LocalLDim();
#ifdef HAVE_OPENMP
        #pragma omp parallel for 
#endif
        for( Int j=0; j<width; ++j )
        {
            T* destCol = &thisLocalBuffer[j*thisLDim];
            const T* sourceCol = &ALocalBuffer[colShift+j*ALDim];
            for( Int iLocal=0; iLocal<localHeight; ++iLocal )
                destCol[iLocal] = sourceCol[iLocal*lcm];
        }
    }
#ifndef RELEASE
    PopCallStack();
#endif
    return *this;
}

inline void AddInLocalData
( const DistMatrix<F,VC,STAR>& X1, DistMatrix<F,STAR,STAR>& Z )
{
#ifndef RELEASE
    PushCallStack("internal::AddInLocalData");
#endif
    const int width = X1.Width();
    const int localHeight = X1.LocalHeight();
    const int stride = X1.Grid().Size();
    const int offset = X1.ColShift();
    for( int j=0; j<width; ++j )
    {
        F* ZColBuffer = Z.LocalBuffer(0,j);
        const F* X1ColBuffer = X1.LockedLocalBuffer(0,j);
        for( int iLocal=0; iLocal<localHeight; ++iLocal )
            ZColBuffer[offset+stride*iLocal] += X1ColBuffer[iLocal];
    }
#ifndef RELEASE
    PopCallStack();
#endif
}