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lammps/lib/kokkos/containers/src/impl/Kokkos_Bitset_impl.hpp
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Kokkos_Bitset_impl.hpp
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/*
//@HEADER
// ************************************************************************
//
// Kokkos v. 2.0
// Copyright (2014) Sandia Corporation
//
// Under the terms of Contract DE-AC04-94AL85000 with Sandia Corporation,
// the U.S. Government retains certain rights in this software.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// 1. Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
//
// 3. Neither the name of the Corporation nor the names of the
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY SANDIA CORPORATION "AS IS" AND ANY
// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
// PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL SANDIA CORPORATION OR THE
// CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
// EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
// PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
// Questions? Contact H. Carter Edwards (hcedwar@sandia.gov)
//
// ************************************************************************
//@HEADER
*/
#ifndef KOKKOS_BITSET_IMPL_HPP
#define KOKKOS_BITSET_IMPL_HPP
#include <Kokkos_Macros.hpp>
#include <stdint.h>
#include <cstdio>
#include <climits>
#include <iostream>
#include <iomanip>
namespace Kokkos { namespace Impl {
KOKKOS_FORCEINLINE_FUNCTION
unsigned rotate_right(unsigned i, int r)
{
enum { size = static_cast<int>(sizeof(unsigned)*CHAR_BIT) };
return r ? ((i >> r) | (i << (size-r))) : i ;
}
KOKKOS_FORCEINLINE_FUNCTION
int bit_scan_forward(unsigned i)
{
#if defined( __CUDA_ARCH__ )
return __ffs(i) - 1;
#elif defined( __GNUC__ ) || defined( __GNUG__ )
return __builtin_ffs(i) - 1;
#elif defined( __INTEL_COMPILER )
return _bit_scan_forward(i);
#else
unsigned t = 1u;
int r = 0;
while (i && (i & t == 0))
{
t = t << 1;
++r;
}
return r;
#endif
}
KOKKOS_FORCEINLINE_FUNCTION
int bit_scan_reverse(unsigned i)
{
enum { shift = static_cast<int>(sizeof(unsigned)*CHAR_BIT - 1) };
#if defined( __CUDA_ARCH__ )
return shift - __clz(i);
#elif defined( __GNUC__ ) || defined( __GNUG__ )
return shift - __builtin_clz(i);
#elif defined( __INTEL_COMPILER )
return _bit_scan_reverse(i);
#else
unsigned t = 1u << shift;
int r = 0;
while (i && (i & t == 0))
{
t = t >> 1;
++r;
}
return r;
#endif
}
// count the bits set
KOKKOS_FORCEINLINE_FUNCTION
int popcount(unsigned i)
{
#if defined( __CUDA_ARCH__ )
return __popc(i);
#elif defined( __GNUC__ ) || defined( __GNUG__ )
return __builtin_popcount(i);
#elif defined ( __INTEL_COMPILER )
return _popcnt32(i);
#else
// http://graphics.stanford.edu/~seander/bithacks.html#CountBitsSetNaive
i = i - ((i >> 1) & ~0u/3u); // temp
i = (i & ~0u/15u*3u) + ((i >> 2) & ~0u/15u*3u); // temp
i = (i + (i >> 4)) & ~0u/255u*15u; // temp
return (int)((i * (~0u/255u)) >> (sizeof(unsigned) - 1) * CHAR_BIT); // count
#endif
}
template <typename Bitset>
struct BitsetCount
{
typedef Bitset bitset_type;
typedef typename bitset_type::execution_space::execution_space execution_space;
typedef typename bitset_type::size_type size_type;
typedef size_type value_type;
bitset_type m_bitset;
BitsetCount( bitset_type const& bitset)
: m_bitset(bitset)
{}
size_type apply() const
{
size_type count = 0u;
parallel_reduce(m_bitset.m_blocks.dimension_0(), *this, count);
return count;
}
KOKKOS_INLINE_FUNCTION
static void init( value_type & count)
{
count = 0u;
}
KOKKOS_INLINE_FUNCTION
static void join( volatile value_type & count, const volatile size_type & incr )
{
count += incr;
}
KOKKOS_INLINE_FUNCTION
void operator()( size_type i, value_type & count) const
{
count += popcount(m_bitset.m_blocks[i]);
}
};
}} //Kokkos::Impl
#endif // KOKKOS_BITSET_IMPL_HPP
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