void Gather
( const BlockMatrix<T>& A,
DistMatrix<T,CIRC,CIRC,BLOCK>& B )
{
DEBUG_ONLY(CSE cse("copy::Gather"))
AssertSameGrids( A, B );
if( A.DistSize() == 1 && A.CrossSize() == 1 )
{
B.Resize( A.Height(), A.Width() );
if( B.CrossRank() == B.Root() )
Copy( A.LockedMatrix(), B.Matrix() );
return;
}
const Int height = A.Height();
const Int width = A.Width();
B.SetGrid( A.Grid() );
B.Resize( height, width );
// Gather the colShifts and rowShifts
// ==================================
Int myShifts[2];
myShifts[0] = A.ColShift();
myShifts[1] = A.RowShift();
vector<Int> shifts;
const Int crossSize = B.CrossSize();
if( B.CrossRank() == B.Root() )
shifts.resize( 2*crossSize );
mpi::Gather( myShifts, 2, shifts.data(), 2, B.Root(), B.CrossComm() );
// Gather the payload data
// =======================
const bool irrelevant = ( A.RedundantRank()!=0 || A.CrossRank()!=A.Root() );
int totalSend = ( irrelevant ? 0 : A.LocalHeight()*A.LocalWidth() );
vector<int> recvCounts, recvOffsets;
if( B.CrossRank() == B.Root() )
recvCounts.resize( crossSize );
mpi::Gather( &totalSend, 1, recvCounts.data(), 1, B.Root(), B.CrossComm() );
int totalRecv = Scan( recvCounts, recvOffsets );
//vector<T> sendBuf(totalSend), recvBuf(totalRecv);
vector<T> sendBuf, recvBuf;
sendBuf.reserve( totalSend );
recvBuf.reserve( totalRecv );
if( !irrelevant )
copy::util::InterleaveMatrix
( A.LocalHeight(), A.LocalWidth(),
A.LockedBuffer(), 1, A.LDim(),
sendBuf.data(), 1, A.LocalHeight() );
mpi::Gather
( sendBuf.data(), totalSend,
recvBuf.data(), recvCounts.data(), recvOffsets.data(),
B.Root(), B.CrossComm() );
// Unpack
// ======
const Int mb = A.BlockHeight();
const Int nb = A.BlockWidth();
const Int colCut = A.ColCut();
const Int rowCut = A.RowCut();
if( B.Root() == B.CrossRank() )
{
for( Int q=0; q<crossSize; ++q )
{
if( recvCounts[q] == 0 )
continue;
const Int colShift = shifts[2*q+0];
const Int rowShift = shifts[2*q+1];
const Int colStride = A.ColStride();
const Int rowStride = A.RowStride();
const Int localHeight =
BlockedLength( height, colShift, mb, colCut, colStride );
const Int localWidth =
BlockedLength( width, rowShift, nb, rowCut, rowStride );
const T* data = &recvBuf[recvOffsets[q]];
for( Int jLoc=0; jLoc<localWidth; ++jLoc )
{
const Int jBefore = rowShift*nb - rowCut;
const Int jLocAdj = ( rowShift==0 ? jLoc+rowCut : jLoc );
const Int numFilledLocalBlocks = jLocAdj / nb;
const Int jMid = numFilledLocalBlocks*nb*rowStride;
const Int jPost = jLocAdj-numFilledLocalBlocks*nb;
const Int j = jBefore + jMid + jPost;
const T* sourceCol = &data[jLoc*localHeight];
for( Int iLoc=0; iLoc<localHeight; ++iLoc )
{
const Int iBefore = colShift*mb - colCut;
const Int iLocAdj = (colShift==0 ? iLoc+colCut : iLoc);
const Int numFilledLocalBlocks = iLocAdj / mb;
const Int iMid = numFilledLocalBlocks*mb*colStride;
const Int iPost = iLocAdj-numFilledLocalBlocks*mb;
const Int i = iBefore + iMid + iPost;
B.SetLocal(i,j,sourceCol[iLoc]);
}
}
}
}
}
void Gather
( const ElementalMatrix<T>& A,
DistMatrix<T,CIRC,CIRC>& B )
{
DEBUG_ONLY(CSE cse("copy::Gather"))
AssertSameGrids( A, B );
if( A.DistSize() == 1 && A.CrossSize() == 1 )
{
B.Resize( A.Height(), A.Width() );
if( B.CrossRank() == B.Root() )
Copy( A.LockedMatrix(), B.Matrix() );
return;
}
const Int height = A.Height();
const Int width = A.Width();
B.SetGrid( A.Grid() );
B.Resize( height, width );
// Gather the colShifts and rowShifts
// ==================================
Int myShifts[2];
myShifts[0] = A.ColShift();
myShifts[1] = A.RowShift();
vector<Int> shifts;
const Int crossSize = B.CrossSize();
if( B.CrossRank() == B.Root() )
shifts.resize( 2*crossSize );
mpi::Gather( myShifts, 2, shifts.data(), 2, B.Root(), B.CrossComm() );
// Gather the payload data
// =======================
const bool irrelevant = ( A.RedundantRank()!=0 || A.CrossRank()!=A.Root() );
int totalSend = ( irrelevant ? 0 : A.LocalHeight()*A.LocalWidth() );
vector<int> recvCounts, recvOffsets;
if( B.CrossRank() == B.Root() )
recvCounts.resize( crossSize );
mpi::Gather( &totalSend, 1, recvCounts.data(), 1, B.Root(), B.CrossComm() );
int totalRecv = Scan( recvCounts, recvOffsets );
//vector<T> sendBuf(totalSend), recvBuf(totalRecv);
vector<T> sendBuf, recvBuf;
sendBuf.reserve( totalSend );
recvBuf.reserve( totalRecv );
if( !irrelevant )
copy::util::InterleaveMatrix
( A.LocalHeight(), A.LocalWidth(),
A.LockedBuffer(), 1, A.LDim(),
sendBuf.data(), 1, A.LocalHeight() );
mpi::Gather
( sendBuf.data(), totalSend,
recvBuf.data(), recvCounts.data(), recvOffsets.data(),
B.Root(), B.CrossComm() );
// Unpack
// ======
if( B.Root() == B.CrossRank() )
{
for( Int q=0; q<crossSize; ++q )
{
if( recvCounts[q] == 0 )
continue;
const Int colShift = shifts[2*q+0];
const Int rowShift = shifts[2*q+1];
const Int colStride = A.ColStride();
const Int rowStride = A.RowStride();
const Int localHeight = Length( height, colShift, colStride );
const Int localWidth = Length( width, rowShift, rowStride );
copy::util::InterleaveMatrix
( localHeight, localWidth,
&recvBuf[recvOffsets[q]], 1, localHeight,
B.Buffer(colShift,rowShift), colStride, rowStride*B.LDim() );
}
}
}