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lammps/lib/kokkos/containers/src/Kokkos_StaticCrsGraph.hpp

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// Kokkos v. 2.0
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#ifndef KOKKOS_STATICCRSGRAPH_HPP
#define KOKKOS_STATICCRSGRAPH_HPP
#include <string>
#include <vector>
#include <Kokkos_Core.hpp>
namespace Kokkos {
namespace Impl {
template<class RowOffsetsType, class RowBlockOffsetsType>
struct StaticCrsGraphBalancerFunctor {
typedef typename RowOffsetsType::non_const_value_type int_type;
RowOffsetsType row_offsets;
RowBlockOffsetsType row_block_offsets;
int_type cost_per_row, num_blocks;
StaticCrsGraphBalancerFunctor(RowOffsetsType row_offsets_,
RowBlockOffsetsType row_block_offsets_,
int_type cost_per_row_, int_type num_blocks_):
row_offsets(row_offsets_),
row_block_offsets(row_block_offsets_),
cost_per_row(cost_per_row_),
num_blocks(num_blocks_){}
KOKKOS_INLINE_FUNCTION
void operator() (const int_type& iRow) const {
const int_type num_rows = row_offsets.dimension_0()-1;
const int_type num_entries = row_offsets(num_rows);
const int_type total_cost = num_entries + num_rows*cost_per_row;
const double cost_per_workset = 1.0*total_cost/num_blocks;
const int_type row_cost = row_offsets(iRow+1)-row_offsets(iRow) + cost_per_row;
int_type count = row_offsets(iRow+1) + cost_per_row*iRow;
if(iRow == num_rows-1) row_block_offsets(num_blocks) = num_rows;
if(true) {
int_type current_block = (count-row_cost-cost_per_row)/cost_per_workset;
int_type end_block = count/cost_per_workset;
// Handle some corner cases for the last two blocks.
if(current_block >= num_blocks-2) {
if((current_block == num_blocks-2) && (count >= (current_block + 1) * cost_per_workset)) {
int_type row = iRow;
int_type cc = count-row_cost-cost_per_row;
int_type block = cc/cost_per_workset;
while((block>0) && (block==current_block)) {
cc = row_offsets(row)+row*cost_per_row;
block = cc/cost_per_workset;
row--;
}
if((count-cc-row_cost-cost_per_row) < num_entries-row_offsets(iRow+1)) {
row_block_offsets(current_block+1) = iRow+1;
} else {
row_block_offsets(current_block+1) = iRow;
}
}
} else {
if((count >= (current_block + 1) * cost_per_workset) ||
(iRow+2 == row_offsets.dimension_0())) {
if(end_block>current_block+1) {
int_type num_block = end_block-current_block;
row_block_offsets(current_block+1) = iRow;
for(int_type block = current_block+2; block <= end_block; block++)
if((block<current_block+2+(num_block-1)/2))
row_block_offsets(block) = iRow;
else
row_block_offsets(block) = iRow+1;
} else {
row_block_offsets(current_block+1) = iRow+1;
}
}
}
}
}
};
}
/// \class GraphRowViewConst
/// \brief View of a row of a sparse graph.
/// \tparam GraphType Sparse graph type, such as (but not limited to) StaticCrsGraph.
///
/// This class provides a generic view of a row of a sparse graph.
/// We intended this class to view a row of a StaticCrsGraph, but
/// GraphType need not necessarily be CrsMatrix.
///
/// The row view is suited for computational kernels like sparse
/// matrix-vector multiply, as well as for modifying entries in the
/// sparse matrix. The view is always const as it does not allow graph modification.
///
/// Here is an example loop over the entries in the row:
/// \code
/// typedef typename GraphRowViewConst<MatrixType>::ordinal_type ordinal_type;
///
/// GraphRowView<GraphType> G_i = ...;
/// const ordinal_type numEntries = G_i.length;
/// for (ordinal_type k = 0; k < numEntries; ++k) {
/// ordinal_type j = G_i.colidx (k);
/// // ... do something with A_ij and j ...
/// }
/// \endcode
///
/// GraphType must provide the \c data_type
/// typedefs. In addition, it must make sense to use GraphRowViewConst to
/// view a row of GraphType. In particular, column
/// indices of a row must be accessible using the <tt>entries</tt>
/// resp. <tt>colidx</tt> arrays given to the constructor of this
/// class, with a constant <tt>stride</tt> between successive entries.
/// The stride is one for the compressed sparse row storage format (as
/// is used by CrsMatrix), but may be greater than one for other
/// sparse matrix storage formats (e.g., ELLPACK or jagged diagonal).
template<class GraphType>
struct GraphRowViewConst {
//! The type of the column indices in the row.
typedef const typename GraphType::data_type ordinal_type;
private:
//! Array of (local) column indices in the row.
ordinal_type* colidx_;
/// \brief Stride between successive entries in the row.
///
/// For compressed sparse row (CSR) storage, this is always one.
/// This might be greater than one for storage formats like ELLPACK
/// or Jagged Diagonal. Nevertheless, the stride can never be
/// greater than the number of rows or columns in the matrix. Thus,
/// \c ordinal_type is the correct type.
const ordinal_type stride_;
public:
/// \brief Constructor
///
/// \param values [in] Array of the row's values.
/// \param colidx [in] Array of the row's column indices.
/// \param stride [in] (Constant) stride between matrix entries in
/// each of the above arrays.
/// \param count [in] Number of entries in the row.
KOKKOS_INLINE_FUNCTION
GraphRowViewConst ( ordinal_type* const colidx_in,
const ordinal_type& stride,
const ordinal_type& count) :
colidx_ (colidx_in), stride_ (stride), length (count)
{}
/// \brief Constructor with offset into \c colidx array
///
/// \param colidx [in] Array of the row's column indices.
/// \param stride [in] (Constant) stride between matrix entries in
/// each of the above arrays.
/// \param count [in] Number of entries in the row.
/// \param idx [in] Start offset into \c colidx array
///
/// \tparam OffsetType The type of \c idx (see above). Must be a
/// built-in integer type. This may differ from ordinal_type.
/// For example, the matrix may have dimensions that fit in int,
/// but a number of entries that does not fit in int.
template<class OffsetType>
KOKKOS_INLINE_FUNCTION
GraphRowViewConst ( const typename GraphType::entries_type& colidx_in,
const ordinal_type& stride,
const ordinal_type& count,
const OffsetType& idx,
const typename std::enable_if<std::is_integral<OffsetType>::value, int>::type& = 0) :
colidx_ (&colidx_in(idx)), stride_ (stride), length (count)
{}
/// \brief Number of entries in the row.
///
/// This is a public const field rather than a public const method,
/// in order to avoid possible overhead of a method call if the
/// compiler is unable to inline that method call.
///
/// We assume that rows contain no duplicate entries (i.e., entries
/// with the same column index). Thus, a row may have up to
/// A.numCols() entries. This means that the correct type of
/// 'length' is ordinal_type.
const ordinal_type length;
/// \brief (Const) reference to the column index of entry i in this
/// row of the sparse matrix.
///
/// "Entry i" is not necessarily the entry with column index i, nor
/// does i necessarily correspond to the (local) row index.
KOKKOS_INLINE_FUNCTION
ordinal_type& colidx (const ordinal_type& i) const {
return colidx_[i*stride_];
}
/// \brief An alias for colidx
KOKKOS_INLINE_FUNCTION
ordinal_type& operator()(const ordinal_type& i) const {
return colidx(i);
}
};
/// \class StaticCrsGraph
/// \brief Compressed row storage array.
///
/// \tparam DataType The type of stored entries. If a StaticCrsGraph is
/// used as the graph of a sparse matrix, then this is usually an
/// integer type, the type of the column indices in the sparse
/// matrix.
///
/// \tparam Arg1Type The second template parameter, corresponding
/// either to the Device type (if there are no more template
/// parameters) or to the Layout type (if there is at least one more
/// template parameter).
///
/// \tparam Arg2Type The third template parameter, which if provided
/// corresponds to the Device type.
///
/// \tparam SizeType The type of row offsets. Usually the default
/// parameter suffices. However, setting a nondefault value is
/// necessary in some cases, for example, if you want to have a
/// sparse matrices with dimensions (and therefore column indices)
/// that fit in \c int, but want to store more than <tt>INT_MAX</tt>
/// entries in the sparse matrix.
///
/// A row has a range of entries:
/// <ul>
/// <li> <tt> row_map[i0] <= entry < row_map[i0+1] </tt> </li>
/// <li> <tt> 0 <= i1 < row_map[i0+1] - row_map[i0] </tt> </li>
/// <li> <tt> entries( entry , i2 , i3 , ... ); </tt> </li>
/// <li> <tt> entries( row_map[i0] + i1 , i2 , i3 , ... ); </tt> </li>
/// </ul>
template< class DataType,
class Arg1Type,
class Arg2Type = void,
typename SizeType = typename ViewTraits<DataType*, Arg1Type, Arg2Type, void >::size_type>
class StaticCrsGraph {
private:
typedef ViewTraits<DataType*, Arg1Type, Arg2Type, void> traits;
public:
typedef DataType data_type;
typedef typename traits::array_layout array_layout;
typedef typename traits::execution_space execution_space;
typedef typename traits::device_type device_type;
typedef SizeType size_type;
typedef StaticCrsGraph< DataType , Arg1Type , Arg2Type , SizeType > staticcrsgraph_type;
typedef StaticCrsGraph< DataType , array_layout , typename traits::host_mirror_space , SizeType > HostMirror;
typedef View< const size_type* , array_layout, device_type > row_map_type;
typedef View< DataType* , array_layout, device_type > entries_type;
typedef View< const size_type* , array_layout, device_type > row_block_type;
entries_type entries;
row_map_type row_map;
row_block_type row_block_offsets;
//! Construct an empty view.
StaticCrsGraph () : entries(), row_map(), row_block_offsets() {}
//! Copy constructor (shallow copy).
StaticCrsGraph (const StaticCrsGraph& rhs) : entries (rhs.entries), row_map (rhs.row_map),
row_block_offsets(rhs.row_block_offsets)
{}
template<class EntriesType, class RowMapType>
StaticCrsGraph (const EntriesType& entries_,const RowMapType& row_map_) : entries (entries_), row_map (row_map_),
row_block_offsets()
{}
/** \brief Assign to a view of the rhs array.
* If the old view is the last view
* then allocated memory is deallocated.
*/
StaticCrsGraph& operator= (const StaticCrsGraph& rhs) {
entries = rhs.entries;
row_map = rhs.row_map;
row_block_offsets = rhs.row_block_offsets;
return *this;
}
/** \brief Destroy this view of the array.
* If the last view then allocated memory is deallocated.
*/
~StaticCrsGraph() {}
/** \brief Return number of rows in the graph
*/
KOKKOS_INLINE_FUNCTION
size_type numRows() const {
return (row_map.dimension_0 () != 0) ?
row_map.dimension_0 () - static_cast<size_type> (1) :
static_cast<size_type> (0);
}
/// \brief Return a const view of row i of the graph.
///
/// If row i does not belong to the graph, return an empty view.
///
/// The returned object \c view implements the following interface:
/// <ul>
/// <li> \c view.length is the number of entries in the row </li>
/// <li> \c view.colidx(k) returns a const reference to the
/// column index of the k-th entry in the row </li>
/// </ul>
/// k is not a column index; it just counts from 0 to
/// <tt>view.length - 1</tt>.
///
/// Users should not rely on the return type of this method. They
/// should instead assign to 'auto'. That allows compile-time
/// polymorphism for different kinds of sparse matrix formats (e.g.,
/// ELLPACK or Jagged Diagonal) that we may wish to support in the
/// future.
KOKKOS_INLINE_FUNCTION
GraphRowViewConst<StaticCrsGraph> rowConst (const data_type i) const {
const size_type start = row_map(i);
// count is guaranteed to fit in ordinal_type, as long as no row
// has duplicate entries.
const data_type count = static_cast<data_type> (row_map(i+1) - start);
if (count == 0) {
return GraphRowViewConst<StaticCrsGraph> (NULL, 1, 0);
} else {
return GraphRowViewConst<StaticCrsGraph> (entries, 1, count, start);
}
}
/** \brief Create a row partitioning into a given number of blocks
* balancing non-zeros + a fixed cost per row.
*/
void create_block_partitioning(size_type num_blocks, size_type fix_cost_per_row = 4) {
View< size_type* , array_layout, device_type >
block_offsets("StatisCrsGraph::load_balance_offsets",num_blocks+1);
Impl::StaticCrsGraphBalancerFunctor<row_map_type,View< size_type* , array_layout, device_type > >
partitioner(row_map,block_offsets,fix_cost_per_row,num_blocks);
Kokkos::parallel_for(Kokkos::RangePolicy<execution_space>(0,numRows()),partitioner);
Kokkos::fence();
row_block_offsets = block_offsets;
}
};
//----------------------------------------------------------------------------
template< class StaticCrsGraphType , class InputSizeType >
typename StaticCrsGraphType::staticcrsgraph_type
create_staticcrsgraph( const std::string & label ,
const std::vector< InputSizeType > & input );
template< class StaticCrsGraphType , class InputSizeType >
typename StaticCrsGraphType::staticcrsgraph_type
create_staticcrsgraph( const std::string & label ,
const std::vector< std::vector< InputSizeType > > & input );
//----------------------------------------------------------------------------
template< class DataType ,
class Arg1Type ,
class Arg2Type ,
typename SizeType >
typename StaticCrsGraph< DataType , Arg1Type , Arg2Type , SizeType >::HostMirror
create_mirror_view( const StaticCrsGraph<DataType,Arg1Type,Arg2Type,SizeType > & input );
template< class DataType ,
class Arg1Type ,
class Arg2Type ,
typename SizeType >
typename StaticCrsGraph< DataType , Arg1Type , Arg2Type , SizeType >::HostMirror
create_mirror( const StaticCrsGraph<DataType,Arg1Type,Arg2Type,SizeType > & input );
} // namespace Kokkos
//----------------------------------------------------------------------------
//----------------------------------------------------------------------------
#include <impl/Kokkos_StaticCrsGraph_factory.hpp>
//----------------------------------------------------------------------------
//----------------------------------------------------------------------------
namespace Kokkos {
namespace Impl {
template< class GraphType >
struct StaticCrsGraphMaximumEntry {
typedef typename GraphType::execution_space execution_space ;
typedef typename GraphType::data_type value_type ;
const typename GraphType::entries_type entries ;
StaticCrsGraphMaximumEntry( const GraphType & graph ) : entries( graph.entries ) {}
KOKKOS_INLINE_FUNCTION
void operator()( const unsigned i , value_type & update ) const
{ if ( update < entries(i) ) update = entries(i); }
KOKKOS_INLINE_FUNCTION
void init( value_type & update ) const
{ update = 0 ; }
KOKKOS_INLINE_FUNCTION
void join( volatile value_type & update ,
volatile const value_type & input ) const
{ if ( update < input ) update = input ; }
};
}
template< class DataType, class Arg1Type, class Arg2Type, typename SizeType >
DataType maximum_entry( const StaticCrsGraph< DataType , Arg1Type , Arg2Type , SizeType > & graph )
{
typedef StaticCrsGraph<DataType,Arg1Type,Arg2Type,SizeType> GraphType ;
typedef Impl::StaticCrsGraphMaximumEntry< GraphType > FunctorType ;
DataType result = 0 ;
Kokkos::parallel_reduce( graph.entries.dimension_0(),
FunctorType(graph), result );
return result ;
}
} // namespace Kokkos
//----------------------------------------------------------------------------
//----------------------------------------------------------------------------
#endif /* #ifndef KOKKOS_CRSARRAY_HPP */