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amg.hpp
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#ifndef VIENNACL_LINALG_OPENCL_KERNELS_AMG_HPP
#define VIENNACL_LINALG_OPENCL_KERNELS_AMG_HPP
#include "viennacl/tools/tools.hpp"
#include "viennacl/ocl/kernel.hpp"
#include "viennacl/ocl/platform.hpp"
#include "viennacl/ocl/utils.hpp"
#include "viennacl/linalg/opencl/common.hpp"
namespace viennacl
{
namespace linalg
{
namespace opencl
{
namespace kernels
{
template<typename StringT>
void generate_amg_influence_trivial(StringT & source)
{
source.append("__kernel void amg_influence_trivial( \n");
source.append(" __global const unsigned int * A_row_indices, \n");
source.append(" __global const unsigned int * A_col_indices, \n");
source.append(" unsigned int A_size1, \n");
source.append(" unsigned int A_nnz, \n");
source.append(" __global unsigned int * influences_row, \n");
source.append(" __global unsigned int * influences_id, \n");
source.append(" __global unsigned int * influences_values) { \n");
source.append(" for (unsigned int i = get_global_id(0); i < A_size1; i += get_global_size(0)) \n");
source.append(" { \n");
source.append(" unsigned int tmp = A_row_indices[i]; \n");
source.append(" influences_row[i] = tmp; \n");
source.append(" influences_values[i] = A_row_indices[i+1] - tmp; \n");
source.append(" } \n");
source.append(" for (unsigned int i = get_global_id(0); i < A_nnz; i += get_global_size(0)) \n");
source.append(" influences_id[i] = A_col_indices[i]; \n");
source.append(" if (get_global_id(0) == 0) \n");
source.append(" influences_row[A_size1] = A_row_indices[A_size1]; \n");
source.append("} \n");
}
template<typename StringT>
void generate_amg_pmis2_init_workdata(StringT & source)
{
source.append("__kernel void amg_pmis2_init_workdata( \n");
source.append(" __global unsigned int *work_state, \n");
source.append(" __global unsigned int *work_random, \n");
source.append(" __global unsigned int *work_index, \n");
source.append(" __global unsigned int const *point_types, \n");
source.append(" __global unsigned int const *random_weights, \n");
source.append(" unsigned int size) { \n");
source.append(" for (unsigned int i = get_global_id(0); i < size; i += get_global_size(0)) { \n");
source.append(" switch (point_types[i]) { \n");
source.append(" case 0: work_state[i] = 1; break; \n"); //viennacl::linalg::detail::amg::amg_level_context::POINT_TYPE_UNDECIDED
source.append(" case 1: work_state[i] = 2; break; \n"); //viennacl::linalg::detail::amg::amg_level_context::POINT_TYPE_COARSE
source.append(" case 2: work_state[i] = 0; break; \n"); //viennacl::linalg::detail::amg::amg_level_context::POINT_TYPE_FINE
source.append(" default: break; // do nothing \n");
source.append(" } \n");
source.append(" work_random[i] = random_weights[i]; \n");
source.append(" work_index[i] = i; \n");
source.append(" } \n");
source.append("} \n");
}
template<typename StringT>
void generate_amg_pmis2_max_neighborhood(StringT & source)
{
source.append("__kernel void amg_pmis2_max_neighborhood( \n");
source.append(" __global unsigned int *work_state, \n");
source.append(" __global unsigned int *work_random, \n");
source.append(" __global unsigned int *work_index, \n");
source.append(" __global unsigned int *work_state2, \n");
source.append(" __global unsigned int *work_random2, \n");
source.append(" __global unsigned int *work_index2, \n");
source.append(" __global unsigned int const *influences_row, \n");
source.append(" __global unsigned int const *influences_id, \n");
source.append(" unsigned int size) { \n");
source.append(" for (unsigned int i = get_global_id(0); i < size; i += get_global_size(0)) { \n");
// load
source.append(" unsigned int state = work_state[i]; \n");
source.append(" unsigned int random = work_random[i]; \n");
source.append(" unsigned int index = work_index[i]; \n");
// max
source.append(" unsigned int j_stop = influences_row[i + 1]; \n");
source.append(" for (unsigned int j = influences_row[i]; j < j_stop; ++j) { \n");
source.append(" unsigned int influenced_point_id = influences_id[j]; \n");
// lexigraphical triple-max (not particularly pretty, but does the job):
source.append(" if (state < work_state[influenced_point_id]) { \n");
source.append(" state = work_state[influenced_point_id]; \n");
source.append(" random = work_random[influenced_point_id]; \n");
source.append(" index = work_index[influenced_point_id]; \n");
source.append(" } else if (state == work_state[influenced_point_id]) { \n");
source.append(" if (random < work_random[influenced_point_id]) { \n");
source.append(" state = work_state[influenced_point_id]; \n");
source.append(" random = work_random[influenced_point_id]; \n");
source.append(" index = work_index[influenced_point_id]; \n");
source.append(" } else if (random == work_random[influenced_point_id]) { \n");
source.append(" if (index < work_index[influenced_point_id]) { \n");
source.append(" state = work_state[influenced_point_id]; \n");
source.append(" random = work_random[influenced_point_id]; \n");
source.append(" index = work_index[influenced_point_id]; \n");
source.append(" } \n");
source.append(" } \n");
source.append(" } \n");
source.append(" }\n"); //for
// store
source.append(" work_state2[i] = state; \n");
source.append(" work_random2[i] = random; \n");
source.append(" work_index2[i] = index; \n");
source.append(" } \n");
source.append("} \n");
}
template<typename StringT>
void generate_amg_pmis2_mark_mis_nodes(StringT & source)
{
source.append("__kernel void amg_pmis2_mark_mis_nodes( \n");
source.append(" __global unsigned int const *work_state, \n");
source.append(" __global unsigned int const *work_index, \n");
source.append(" __global unsigned int *point_types, \n");
source.append(" __global unsigned int *undecided_buffer, \n");
source.append(" unsigned int size) { \n");
source.append(" unsigned int num_undecided = 0; \n");
source.append(" for (unsigned int i = get_global_id(0); i < size; i += get_global_size(0)) { \n");
source.append(" unsigned int max_state = work_state[i]; \n");
source.append(" unsigned int max_index = work_index[i]; \n");
source.append(" if (point_types[i] == 0) { \n"); // viennacl::linalg::detail::amg::amg_level_context::POINT_TYPE_UNDECIDED
source.append(" if (i == max_index) point_types[i] = 1; \n"); // viennacl::linalg::detail::amg::amg_level_context::POINT_TYPE_COARSE
source.append(" else if (max_state == 2) point_types[i] = 2; \n"); // viennacl::linalg::detail::amg::amg_level_context::POINT_TYPE_FINE
source.append(" else num_undecided += 1; \n");
source.append(" } \n");
source.append(" } \n");
// reduction in shared memory:
source.append(" __local unsigned int shared_buffer[256]; \n");
source.append(" shared_buffer[get_local_id(0)] = num_undecided; \n");
source.append(" for (unsigned int stride = get_local_size(0)/2; stride > 0; stride /= 2) { \n");
source.append(" barrier(CLK_LOCAL_MEM_FENCE); \n");
source.append(" if (get_local_id(0) < stride) shared_buffer[get_local_id(0)] += shared_buffer[get_local_id(0)+stride]; \n");
source.append(" } \n");
source.append(" if (get_local_id(0) == 0) \n");
source.append(" undecided_buffer[get_group_id(0)] = shared_buffer[0]; \n");
source.append("} \n");
}
template<typename StringT>
void generate_amg_pmis2_reset_state(StringT & source)
{
source.append("__kernel void amg_pmis2_reset_state( \n");
source.append(" __global unsigned int *point_types, \n");
source.append(" unsigned int size) { \n");
source.append(" for (unsigned int i = get_global_id(0); i < size; i += get_global_size(0)) { \n");
source.append(" if (point_types[i] != 1) point_types[i] = 0;\n"); // mind mapping of POINT_TYPE_COARSE and POINT_TYPE_UNDECIDED
source.append(" } \n");
source.append("} \n");
}
template<typename StringT>
void generate_amg_agg_propagate_coarse_indices(StringT & source)
{
source.append(" __kernel void amg_agg_propagate_coarse_indices( \n");
source.append(" __global unsigned int *point_types, \n");
source.append(" __global unsigned int *coarse_ids, \n");
source.append(" __global unsigned int const *influences_row, \n");
source.append(" __global unsigned int const *influences_id, \n");
source.append(" unsigned int size) { \n");
source.append(" for (unsigned int i = get_global_id(0); i < size; i += get_global_size(0)) \n");
source.append(" { \n");
source.append(" if (point_types[i] == 1) { \n"); //viennacl::linalg::detail::amg::amg_level_context::POINT_TYPE_COARSE
source.append(" unsigned int coarse_index = coarse_ids[i]; \n");
source.append(" unsigned int j_stop = influences_row[i + 1]; \n");
source.append(" for (unsigned int j = influences_row[i]; j < j_stop; ++j) { \n");
source.append(" unsigned int influenced_point_id = influences_id[j]; \n");
source.append(" coarse_ids[influenced_point_id] = coarse_index; \n");
source.append(" if (influenced_point_id != i) point_types[influenced_point_id] = 2; \n"); //viennacl::linalg::detail::amg::amg_level_context::POINT_TYPE_FINE
source.append(" } \n");
source.append(" } \n");
source.append(" } \n");
source.append("} \n");
}
template<typename StringT>
void generate_amg_agg_merge_undecided(StringT & source)
{
source.append(" __kernel void amg_agg_merge_undecided( \n");
source.append(" __global unsigned int *point_types, \n");
source.append(" __global unsigned int *coarse_ids, \n");
source.append(" __global unsigned int const *influences_row, \n");
source.append(" __global unsigned int const *influences_id, \n");
source.append(" unsigned int size) { \n");
source.append(" for (unsigned int i = get_global_id(0); i < size; i += get_global_size(0)) \n");
source.append(" { \n");
source.append(" if (point_types[i] == 0) { \n"); //viennacl::linalg::detail::amg::amg_level_context::POINT_TYPE_UNDECIDED
source.append(" unsigned int j_stop = influences_row[i + 1]; \n");
source.append(" for (unsigned int j = influences_row[i]; j < j_stop; ++j) { \n");
source.append(" unsigned int influenced_point_id = influences_id[j]; \n");
source.append(" if (point_types[influenced_point_id] != 0) { \n"); // viennacl::linalg::detail::amg::amg_level_context::POINT_TYPE_UNDECIDED
source.append(" coarse_ids[i] = coarse_ids[influenced_point_id]; \n");
source.append(" break; \n");
source.append(" } \n");
source.append(" } \n");
source.append(" } \n");
source.append(" } \n");
source.append("} \n");
}
template<typename StringT>
void generate_amg_agg_merge_undecided_2(StringT & source)
{
source.append(" __kernel void amg_agg_merge_undecided_2( \n");
source.append(" __global unsigned int *point_types, \n");
source.append(" unsigned int size) { \n");
source.append(" for (unsigned int i = get_global_id(0); i < size; i += get_global_size(0)) \n");
source.append(" if (point_types[i] == 0) point_types[i] = 2; \n"); // POINT_TYPE_UNDECIDED to POINT_TYPE_FINE
source.append("} \n");
}
template<typename StringT>
void generate_amg_interpol_ag(StringT & source, std::string const & numeric_string)
{
source.append(" __kernel void amg_interpol_ag( \n");
source.append(" __global unsigned int * P_row_indices, \n");
source.append(" __global unsigned int * P_column_indices, \n");
source.append(" __global "); source.append(numeric_string); source.append(" * P_elements, \n");
source.append(" __global const unsigned int * coarse_agg_ids, \n");
source.append(" unsigned int size) { \n");
source.append(" for (unsigned int i = get_global_id(0); i < size; i += get_global_size(0)) \n");
source.append(" { \n");
source.append(" P_row_indices[i] = i; \n");
source.append(" P_column_indices[i] = coarse_agg_ids[i]; \n");
source.append(" P_elements[i] = 1; \n");
source.append(" } \n");
source.append(" if (get_global_id(0) == 0) P_row_indices[size] = size; \n");
source.append(" } \n");
}
template<typename StringT>
void generate_amg_interpol_sa(StringT & source, std::string const & numeric_string)
{
source.append("__kernel void amg_interpol_sa( \n");
source.append(" __global unsigned int const *A_row_indices, \n");
source.append(" __global unsigned int const *A_col_indices, \n");
source.append(" __global "); source.append(numeric_string); source.append(" const *A_elements, \n");
source.append(" unsigned int A_size1, \n");
source.append(" unsigned int A_nnz, \n");
source.append(" __global unsigned int *Jacobi_row_indices, \n");
source.append(" __global unsigned int *Jacobi_col_indices, \n");
source.append(" __global "); source.append(numeric_string); source.append(" *Jacobi_elements, \n");
source.append(" "); source.append(numeric_string); source.append(" omega) { \n");
source.append(" for (unsigned int row = get_global_id(0); row < A_size1; row += get_global_size(0)) \n");
source.append(" { \n");
source.append(" unsigned int row_begin = A_row_indices[row]; \n");
source.append(" unsigned int row_end = A_row_indices[row+1]; \n");
source.append(" Jacobi_row_indices[row] = row_begin; \n");
// Step 1: Extract diagonal:
source.append(" "); source.append(numeric_string); source.append(" diag = 0; \n");
source.append(" for (unsigned int j = row_begin; j < row_end; ++j) { \n");
source.append(" if (A_col_indices[j] == row) { \n");
source.append(" diag = A_elements[j]; \n");
source.append(" break; \n");
source.append(" } \n");
source.append(" } \n");
// Step 2: Write entries:
source.append(" for (unsigned int j = row_begin; j < row_end; ++j) { \n");
source.append(" unsigned int col_index = A_col_indices[j]; \n");
source.append(" Jacobi_col_indices[j] = col_index; \n");
source.append(" Jacobi_elements[j] = (col_index == row) ? (1 - omega) : (-omega * A_elements[j] / diag); \n");
source.append(" } \n");
source.append(" } \n");
source.append(" if (get_global_id(0) == 0) Jacobi_row_indices[A_size1] = A_nnz; \n");
source.append("} \n");
}
// main kernel class
template<typename NumericT>
struct amg
{
static std::string program_name()
{
return viennacl::ocl::type_to_string<NumericT>::apply() + "_amg";
}
static void init(viennacl::ocl::context & ctx)
{
static std::map<cl_context, bool> init_done;
if (!init_done[ctx.handle().get()])
{
viennacl::ocl::DOUBLE_PRECISION_CHECKER<NumericT>::apply(ctx);
std::string numeric_string = viennacl::ocl::type_to_string<NumericT>::apply();
std::string source;
source.reserve(2048);
viennacl::ocl::append_double_precision_pragma<NumericT>(ctx, source);
generate_amg_influence_trivial(source);
generate_amg_pmis2_init_workdata(source);
generate_amg_pmis2_max_neighborhood(source);
generate_amg_pmis2_mark_mis_nodes(source);
generate_amg_pmis2_reset_state(source);
generate_amg_agg_propagate_coarse_indices(source);
generate_amg_agg_merge_undecided(source);
generate_amg_agg_merge_undecided_2(source);
generate_amg_interpol_ag(source, numeric_string);
generate_amg_interpol_sa(source, numeric_string);
std::string prog_name = program_name();
#ifdef VIENNACL_BUILD_INFO
std::cout << "Creating program " << prog_name << std::endl;
#endif
ctx.add_program(source, prog_name);
init_done[ctx.handle().get()] = true;
} //if
} //init
};
} // namespace kernels
} // namespace opencl
} // namespace linalg
} // namespace viennacl
#endif
viennacl::linalg::opencl::kernels::amg
Main kernel class for generating OpenCL kernels for compressed_matrix.
Definition: amg.hpp:346
viennacl::linalg::opencl::kernels::generate_amg_pmis2_reset_state
void generate_amg_pmis2_reset_state(StringT &source)
Definition: amg.hpp:179
platform.hpp
Implements a OpenCL platform within ViennaCL.
tools.hpp
Various little tools used here and there in ViennaCL.
viennacl::ocl::context
Manages an OpenCL context and provides the respective convenience functions for creating buffers...
Definition: context.hpp:55
viennacl::linalg::opencl::kernels::generate_amg_pmis2_init_workdata
void generate_amg_pmis2_init_workdata(StringT &source)
Definition: amg.hpp:54
utils.hpp
Provides OpenCL-related utilities.
viennacl::ocl::context::handle
const viennacl::ocl::handle< cl_context > & handle() const
Returns the context handle.
Definition: context.hpp:611
common.hpp
Common implementations shared by OpenCL-based operations.
viennacl::ocl::DOUBLE_PRECISION_CHECKER::apply
static void apply(viennacl::ocl::context const &)
Definition: utils.hpp:40
viennacl::ocl::handle::get
const OCL_TYPE & get() const
Definition: handle.hpp:191
viennacl::linalg::opencl::kernels::generate_amg_pmis2_mark_mis_nodes
void generate_amg_pmis2_mark_mis_nodes(StringT &source)
Definition: amg.hpp:141
viennacl::linalg::opencl::kernels::generate_amg_agg_merge_undecided_2
void generate_amg_agg_merge_undecided_2(StringT &source)
Definition: amg.hpp:261
viennacl::linalg::opencl::kernels::amg::program_name
static std::string program_name()
Definition: amg.hpp:348
viennacl::linalg::opencl::kernels::generate_amg_influence_trivial
void generate_amg_influence_trivial(StringT &source)
Definition: amg.hpp:24
viennacl::linalg::opencl::kernels::amg::init
static void init(viennacl::ocl::context &ctx)
Definition: amg.hpp:353
kernel.hpp
Representation of an OpenCL kernel in ViennaCL.
viennacl::linalg::opencl::kernels::generate_amg_pmis2_max_neighborhood
void generate_amg_pmis2_max_neighborhood(StringT &source)
Definition: amg.hpp:83
viennacl::linalg::opencl::kernels::generate_amg_agg_merge_undecided
void generate_amg_agg_merge_undecided(StringT &source)
Definition: amg.hpp:230
viennacl::ocl::type_to_string
Helper class for converting a type to its string representation.
Definition: utils.hpp:57
viennacl::linalg::opencl::kernels::generate_amg_interpol_ag
void generate_amg_interpol_ag(StringT &source, std::string const &numeric_string)
Definition: amg.hpp:277
viennacl::linalg::opencl::kernels::generate_amg_interpol_sa
void generate_amg_interpol_sa(StringT &source, std::string const &numeric_string)
Definition: amg.hpp:299
viennacl::linalg::opencl::kernels::generate_amg_agg_propagate_coarse_indices
void generate_amg_agg_propagate_coarse_indices(StringT &source)
Definition: amg.hpp:200