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March 2, 2021 13:53
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Usage of Kokkos::StaticCrsGraph
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#include <vector> | |
#include <cassert> | |
#include <iostream> | |
#include "Kokkos_Core.hpp" | |
#include "Kokkos_StaticCrsGraph.hpp" | |
// StaticGraphType<DataType, Space, Layout, MemoryTrait, SizeType> | |
using Space = Kokkos::DefaultExecutionSpace; | |
using StaticCrsGraphType = Kokkos::StaticCrsGraph<int, Space, void, void, int>; | |
// Ref: https://github.com/kokkos/kokkos/blob/1fb0c284d458c75370094921d9f202c287502325/containers/src/Kokkos_StaticCrsGraph.hpp | |
// Ref: https://github.com/kokkos/kokkos/blob/1fb0c284d458c75370094921d9f202c287502325/containers/unit_tests/TestStaticCrsGraph.hpp | |
int main(int argc, char* argv[]) { | |
Kokkos::initialize(argc, argv); | |
{ | |
const int n = 100; | |
std::vector<std::vector<int>> graph(n); | |
for (int i = 0; i < n; ++i) { | |
for (int j = 0; j < i; ++j) { | |
graph[i].emplace_back(i); | |
} | |
} | |
StaticCrsGraphType d_graph; | |
StaticCrsGraphType::HostMirror h_graph; | |
d_graph = Kokkos::create_staticcrsgraph<StaticCrsGraphType>("d_graph", graph); | |
assert(d_graph.is_allocated()); | |
h_graph = Kokkos::create_mirror(d_graph); | |
assert(h_graph.numRows() == n); | |
for (int i = 0; i < n; ++i) { | |
// StaticCrsGraph.row_map[i] is the position of the first element in the i-th row | |
const int begin = h_graph.row_map[i]; | |
const int end = h_graph.row_map[i + 1]; | |
assert(end - begin == graph[i].size()); | |
auto rowView = h_graph.rowConst(i); // just use "auto" here | |
assert((int)rowView.length == end - begin); | |
for (int j = 0; j < rowView.length; ++j) { | |
assert(rowView.colidx(j) == graph[i][j]); | |
assert(rowView(j) == graph[i][j]); // alias for colidx | |
} | |
} | |
int sum = 0; | |
using team_policy = Kokkos::TeamPolicy<>; | |
using member_type = team_policy::member_type; | |
Kokkos::parallel_reduce("sum_graph", | |
team_policy(n, Kokkos::AUTO), | |
KOKKOS_LAMBDA(const member_type& teamMember, int& update) { | |
const int row = teamMember.league_rank(); | |
auto rowView = d_graph.rowConst(row); | |
int tmpSum = 0; | |
Kokkos::parallel_reduce( | |
Kokkos::TeamThreadRange(teamMember, rowView.length), | |
[=] (const int ii, int& innerTmpSum) { // no need to capture reference here | |
innerTmpSum += rowView(ii); | |
}, | |
tmpSum | |
); | |
if (teamMember.team_rank() == 0) { | |
update += tmpSum; | |
} | |
}, | |
sum | |
); | |
std::cout << "Sum (actual): " << sum << std::endl; | |
int expect = (n - 1) * n * (2 * n - 1) / 6; | |
std::cout << "Sum (expect): " << expect << std::endl; | |
assert(sum == expect); | |
} // need to deallocate views before Kokkos::finalize is called! | |
Kokkos::finalize(); | |
return 0; | |
} |
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