void PartialRowScatter
( T alpha,
const ElementalMatrix<T>& A,
ElementalMatrix<T>& B )
{
DEBUG_ONLY(CSE cse("axpy_contract::PartialRowScatter"))
AssertSameGrids( A, B );
if( A.Height() != B.Height() || A.Width() != B.Width() )
LogicError("Matrix sizes did not match");
if( !B.Participating() )
return;
if( B.RowAlign() % A.RowStride() == A.RowAlign() )
{
const Int rowStride = B.RowStride();
const Int rowStridePart = B.PartialRowStride();
const Int rowStrideUnion = B.PartialUnionRowStride();
const Int rowRankPart = B.PartialRowRank();
const Int height = B.Height();
const Int width = B.Width();
const Int maxLocalWidth = MaxLength( width, rowStride );
const Int recvSize = mpi::Pad( height*maxLocalWidth );
const Int sendSize = rowStrideUnion*recvSize;
//vector<T> buffer( sendSize );
vector<T> buffer;
buffer.reserve( sendSize );
// Pack
copy::util::PartialRowStridedPack
( height, width,
B.RowAlign(), rowStride,
rowStrideUnion, rowStridePart, rowRankPart,
A.RowShift(),
A.LockedBuffer(), A.LDim(),
buffer.data(), recvSize );
// Communicate
mpi::ReduceScatter( buffer.data(), recvSize, B.PartialUnionRowComm() );
// Unpack our received data
axpy::util::InterleaveMatrixUpdate
( alpha, height, B.LocalWidth(),
buffer.data(), 1, height,
B.Buffer(), 1, B.LDim() );
}
else
LogicError("Unaligned PartialRowScatter not implemented");
}
