C++ DistMatrix::ColCut方法代碼示例

void GatherSubdiagonal
( const DistMatrix<F,MC,MR,BLOCK>& H,
  const IR& winInd,
        DistMatrix<Base<F>,STAR,STAR>& hSubWin )
{
    DEBUG_CSE
    const Int winSize = winInd.end - winInd.beg;
    const Int blockSize = H.BlockHeight();
    const Grid& grid = H.Grid();
    const auto& HLoc = H.LockedMatrix();
    DEBUG_ONLY(
      if( H.BlockHeight() != H.BlockWidth() )
          LogicError("Assumed square distribution blocks");
      if( H.ColCut() != H.RowCut() )
          LogicError("Assumed symmetric cuts");
      if( blockSize < 2 )
          LogicError("Assumed blocks of size at least two");
    )

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

    const Int blockHeight = H.BlockHeight();
    const Int firstBlockHeight = blockHeight - H.ColCut();
    if( height <= firstBlockHeight || grid.Height() == 1 )
    {
        if( grid.Row() == H.RowOwner(0) )
        {
            // This process row can locally update its portion of H
            Matrix<F> HLocCopy( H.Matrix() );
            Gemm( ADJOINT, NORMAL, F(1), Z, HLocCopy, H.Matrix() );
        }
    }
    else if( height <= firstBlockHeight + blockHeight )
    {
        const bool firstRow = H.RowOwner( 0 );
        const bool secondRow = H.RowOwner( firstBlockHeight );
        if( grid.Row() == firstRow )
        {
            // 
            // Replace H with 
            //
            //   | ZLeft, ZRight |' | HTop    |,
            //                      | HBottom |
            //
            // where HTop is owned by this process row and HBottom by the next.
            //
            auto ZLeft = Z( ALL, IR(0,firstBlockHeight) );

            // Partition space for the combined matrix
            Matrix<F> HCombine( height, H.LocalWidth() );
            auto HTop = HCombine( IR(0,firstBlockHeight), ALL );
            auto HBottom = HCombine( IR(firstBlockHeight,END), ALL );

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

            // Exchange the data
            El::SendRecv( HTop, HBottom, H.ColComm(), secondRow, secondRow );
            
            // Form our portion of the result
            Gemm( ADJOINT, NORMAL, F(1), ZLeft, HCombine, H.Matrix() );
        }
        else if( grid.Row() == secondRow )
        {
            // 
            // Replace H with 
            //
            //   | ZLeft, ZRight |' | HTop    |,
            //                      | HBottom |
            //
            // where HTop is owned by the previous process row and HBottom by
            // this one.
            //
            auto ZRight = Z( ALL, IR(firstBlockHeight,END) );

            // Partition space for the combined matrix
            Matrix<F> HCombine( height, H.LocalWidth() );
            auto HTop = HCombine( IR(0,firstBlockHeight), ALL );
            auto HBottom = HCombine( IR(firstBlockHeight,END), ALL );

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

            // Exchange the data
            El::SendRecv( HBottom, HTop, H.ColComm(), firstRow, firstRow );
            
            // Form our portion of the result
            Gemm( ADJOINT, NORMAL, F(1), ZRight, HCombine, 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,STAR,MR,BLOCK> H_STAR_MR( H );
        Matrix<F> HLocCopy( H_STAR_MR.Matrix() );
        Gemm( ADJOINT, NORMAL, F(1), Z, HLocCopy, H_STAR_MR.Matrix() );
        H = H_STAR_MR;
    }
}

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

    const Int blockHeight = A.BlockHeight();
    const Int firstBlockHeight = blockHeight - A.ColCut();
    if( height <= firstBlockHeight || grid.Height() == 1 )
    {
        if( grid.Row() == A.RowOwner(0) )
        {
            // This process row can locally update its portion of A
            TransformRows( V, A.Matrix() );
        }
    }
    else if( height <= firstBlockHeight + blockHeight )
    {
        const int firstRow = A.RowOwner( 0 );
        const int secondRow = A.RowOwner( firstBlockHeight );
        if( grid.Row() == firstRow )
        {
            //
            // Replace A with
            //
            //   | VLeft, VRight |' | ATop    |,
            //                      | ABottom |
            //
            // where ATop is owned by this process row and ABottom by the next.
            //
            auto VLeft = V( ALL, IR(0,firstBlockHeight) );

            // Partition space for the combined matrix
            Matrix<F> ACombine( height, A.LocalWidth() );
            auto ATop = ACombine( IR(0,firstBlockHeight), ALL );
            auto ABottom = ACombine( IR(firstBlockHeight,END), ALL );

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

            // Exchange the data
            El::SendRecv( ATop, ABottom, A.ColComm(), secondRow, secondRow );

            // Form our portion of the result
            Gemm( ADJOINT, NORMAL, F(1), VLeft, ACombine, A.Matrix() );
        }
        else if( grid.Row() == secondRow )
        {
            //
            // Replace A with
            //
            //   | VLeft, VRight |' | ATop    |,
            //                      | ABottom |
            //
            // where ATop is owned by the previous process row and ABottom by
            // this one.
            //
            auto VRight = V( ALL, IR(firstBlockHeight,END) );

            // Partition space for the combined matrix
            Matrix<F> ACombine( height, A.LocalWidth() );
            auto ATop = ACombine( IR(0,firstBlockHeight), ALL );
            auto ABottom = ACombine( IR(firstBlockHeight,END), ALL );

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

            // Exchange the data
            El::SendRecv( ABottom, ATop, A.ColComm(), firstRow, firstRow );

            // Form our portion of the result
            Gemm( ADJOINT, NORMAL, F(1), VRight, ACombine, 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,STAR,MR,BLOCK> A_STAR_MR( A );
        Matrix<F> ALocCopy( A_STAR_MR.Matrix() );
        Gemm( ADJOINT, NORMAL, F(1), V, ALocCopy, A_STAR_MR.Matrix() );
        A = A_STAR_MR;
    }
}