C++ DistMatrix::ColOwner方法代碼示例

void TransformColumns
( const Matrix<F>& Z,
        DistMatrix<F,MC,MR,BLOCK>& H )
{
    DEBUG_CSE
    const Int width = H.Width();
    const Grid& grid = H.Grid();

    const Int blockWidth = H.BlockWidth();
    const Int firstBlockWidth = blockWidth - H.RowCut();
    if( width <= firstBlockWidth || grid.Width() == 1 )
    {
        if( grid.Col() == H.ColOwner(0) )
        {
            // This process row can locally update its portion of H
            Matrix<F> HLocCopy( H.Matrix() );
            Gemm( NORMAL, NORMAL, F(1), HLocCopy, Z, H.Matrix() );
        }
    }
    else if( width <= firstBlockWidth + blockWidth )
    {
        const bool firstCol = H.ColOwner( 0 );
        const bool secondCol = H.ColOwner( firstBlockWidth );
        if( grid.Col() == firstCol )
        {
            // 
            // Replace H with 
            //
            //   | HLeft, HRight | | ZLeft, ZRight |,
            //
            // where HLeft is owned by this process column and HRight by the
            // next.
            //
            auto ZLeft = Z( ALL, IR(0,firstBlockWidth) );

            // Partition space for the combined matrix
            Matrix<F> HCombine( H.LocalHeight(), width );
            auto HLeft = HCombine( ALL, IR(0,firstBlockWidth) );
            auto HRight = HCombine( ALL, IR(firstBlockWidth,END) );

            // Copy our portion into the combined matrix
            HLeft = H.LockedMatrix();

            // Exchange the data
            El::SendRecv( HLeft, HRight, H.RowComm(), secondCol, secondCol );
            
            // Form our portion of the result
            Gemm( NORMAL, NORMAL, F(1), HCombine, ZLeft, H.Matrix() );
        }
        else if( grid.Col() == secondCol )
        {
            // 
            // Replace H with 
            //
            //   | HLeft, HRight | | ZLeft, ZRight |,
            //
            // where HLeft is owned by the previous process column and HRight
            // by this one.
            //
            auto ZRight = Z( ALL, IR(firstBlockWidth,END) );

            // Partition space for the combined matrix
            Matrix<F> HCombine( H.LocalHeight(), width );
            auto HLeft = HCombine( ALL, IR(0,firstBlockWidth) );
            auto HRight = HCombine( ALL, IR(firstBlockWidth,END) );

            // Copy our portion into the combined matrix
            HRight = H.LockedMatrix();

            // Exchange the data
            El::SendRecv( HRight, HLeft, H.RowComm(), firstCol, firstCol );
            
            // Form our portion of the result
            Gemm( NORMAL, NORMAL, F(1), HCombine, ZRight, H.Matrix() );
        }
    }
    else
    {
        // Fall back to the entire process column interacting.
        // TODO(poulson): Only form the subset of the result that we need.
        DistMatrix<F,MC,STAR,BLOCK> H_MC_STAR( H );
        Matrix<F> HLocCopy( H_MC_STAR.Matrix() );
        Gemm( NORMAL, NORMAL, F(1), HLocCopy, Z, H_MC_STAR.Matrix() );
        H = H_MC_STAR;
    }
}

void TransformColumns
( const Matrix<F>& V,
        DistMatrix<F,MC,MR,BLOCK>& A )
{
    DEBUG_CSE
    const Int width = A.Width();
    const Grid& grid = A.Grid();

    const Int blockWidth = A.BlockWidth();
    const Int firstBlockWidth = blockWidth - A.RowCut();
    if( width <= firstBlockWidth || grid.Width() == 1 )
    {
        if( grid.Col() == A.ColOwner(0) )
        {
            // This process row can locally update its portion of A
            TransformColumns( V, A.Matrix() );
        }
    }
    else if( width <= firstBlockWidth + blockWidth )
    {
        const int firstCol = A.ColOwner( 0 );
        const int secondCol = A.ColOwner( firstBlockWidth );
        if( grid.Col() == firstCol )
        {
            //
            // Replace A with
            //
            //   | ALeft, ARight | | VLeft, VRight |,
            //
            // where ALeft is owned by this process column and ARight by the
            // next.
            //

            // Partition space for the combined matrix
            Matrix<F> ACombine( A.LocalHeight(), width );
            auto ALeft = ACombine( ALL, IR(0,firstBlockWidth) );
            auto ARight = ACombine( ALL, IR(firstBlockWidth,END) );

            // Copy our portion into the combined matrix
            ALeft = A.LockedMatrix();

            // Exchange the data
            El::SendRecv( ALeft, ARight, A.RowComm(), secondCol, secondCol );

            // Form our portion of the result
            auto VLeft = V( ALL, IR(0,firstBlockWidth) );
            Gemm( NORMAL, NORMAL, F(1), ACombine, VLeft, A.Matrix() );
        }
        else if( grid.Col() == secondCol )
        {
            //
            // Replace A with
            //
            //   | ALeft, ARight | | VLeft, VRight |,
            //
            // where ALeft is owned by the previous process column and ARight
            // by this one.
            //

            // Partition space for the combined matrix
            Matrix<F> ACombine( A.LocalHeight(), width );
            auto ALeft = ACombine( ALL, IR(0,firstBlockWidth) );
            auto ARight = ACombine( ALL, IR(firstBlockWidth,END) );

            // Copy our portion into the combined matrix
            ARight = A.LockedMatrix();

            // Exchange the data
            El::SendRecv( ARight, ALeft, A.RowComm(), firstCol, firstCol );

            // Form our portion of the result
            auto VRight = V( ALL, IR(firstBlockWidth,END) );
            Gemm( NORMAL, NORMAL, F(1), ACombine, VRight, A.Matrix() );
        }
    }
    else
    {
        // Fall back to the entire process column interacting.
        // TODO(poulson): Only form the subset of the result that we need.
        DistMatrix<F,MC,STAR,BLOCK> A_MC_STAR( A );
        Matrix<F> ALocCopy( A_MC_STAR.Matrix() );
        Gemm( NORMAL, NORMAL, F(1), ALocCopy, V, A_MC_STAR.Matrix() );
        A = A_MC_STAR;
    }
}