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Merge branch 'master' into mbell/mld_offset_overflow

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Michael Bell 2021-09-21 18:10:36 +01:00 committed by GitHub
commit cd73026125
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3 changed files with 68 additions and 5 deletions
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1
CHANGELOG.md
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@ -8,6 +8,7 @@
- FIXED: Fixed Boost link flags in pkg-config file. [#6083](https://github.com/Project-OSRM/osrm-backend/pull/6083)
- Routing:
- FIXED: Fix generation of inefficient MLD partitions [#6084](https://github.com/Project-OSRM/osrm-backend/pull/6084)
- FIXED: Fix MLD level mask generation to support 64-bit masks. [#6123](https://github.com/Project-OSRM/osrm-backend/pull/6123)
- FIXED: Fix metric offset overflow for large MLD partitions. This breaks the **data format** [#6124](https://github.com/Project-OSRM/osrm-backend/pull/6124)
# 5.25.0

15
include/partitioner/multi_level_partition.hpp
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@ -186,11 +186,12 @@ template <storage::Ownership Ownership> class MultiLevelPartitionImpl final
auto bits = static_cast<std::uint64_t>(std::ceil(std::log2(num_cells + 1)));
offsets[lidx++] = sum_bits;
sum_bits += bits;
if (sum_bits > 64)
if (sum_bits > NUM_PARTITION_BITS)
{
throw util::exception(
"Can't pack the partition information at level " + std::to_string(lidx) +
" into a 64bit integer. Would require " + std::to_string(sum_bits) + " bits.");
" into a " + std::to_string(NUM_PARTITION_BITS) +
"bit integer. Would require " + std::to_string(sum_bits) + " bits.");
}
}
// sentinel
@ -211,11 +212,15 @@ template <storage::Ownership Ownership> class MultiLevelPartitionImpl final
[&](const auto offset, const auto next_offset) {
// create mask that has `bits` ones at its LSBs.
// 000011
BOOST_ASSERT(offset < NUM_PARTITION_BITS);
BOOST_ASSERT(offset <= NUM_PARTITION_BITS);
PartitionID mask = (1ULL << offset) - 1ULL;
// 001111
BOOST_ASSERT(next_offset < NUM_PARTITION_BITS);
PartitionID next_mask = (1ULL << next_offset) - 1ULL;
BOOST_ASSERT(next_offset <= NUM_PARTITION_BITS);
// Check offset for shift overflow. Offsets are strictly increasing,
// so we only need the check on the last mask.
PartitionID next_mask = next_offset == NUM_PARTITION_BITS
? -1ULL
: (1ULL << next_offset) - 1ULL;
// 001100
masks[lidx++] = next_mask ^ mask;
});

57
unit_tests/partitioner/multi_level_partition.cpp
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@ -1,6 +1,8 @@
#include <boost/numeric/conversion/cast.hpp>
#include <boost/test/unit_test.hpp>
#include "util/exception.hpp"
#include "util/for_each_indexed.hpp"
#include <util/integer_range.hpp>
#include <util/msb.hpp>
@ -230,4 +232,59 @@ BOOST_AUTO_TEST_CASE(large_cell_number)
}
}
BOOST_AUTO_TEST_CASE(cell_64_bits)
{
// bits = ceil(log2(2458529 + 1)) + ceil(log2(258451 + 1)) + ceil(log2(16310 + 1)) +
// ceil(log2(534 + 1))
// = 22 + 18 + 14 + 10
// = 64
const size_t NUM_PARTITIONS = 2458529;
const std::vector<size_t> level_cells = {NUM_PARTITIONS, 258451, 16310, 534};
std::vector<std::vector<CellID>> levels(level_cells.size(),
std::vector<CellID>(level_cells[0]));
std::vector<uint32_t> levels_to_num_cells(level_cells.size());
const auto set_level_cells = [&](size_t level, auto const num_cells) {
for (auto val : util::irange<size_t>(0ULL, NUM_PARTITIONS))
{
levels[level][val] = std::min(val, num_cells - 1);
}
levels_to_num_cells[level] = num_cells;
};
util::for_each_indexed(level_cells.cbegin(), level_cells.cend(), set_level_cells);
MultiLevelPartition mlp{levels, levels_to_num_cells};
BOOST_REQUIRE_EQUAL(mlp.GetNumberOfCells(1), level_cells[0]);
BOOST_REQUIRE_EQUAL(mlp.GetNumberOfCells(2), level_cells[1]);
BOOST_REQUIRE_EQUAL(mlp.GetNumberOfCells(3), level_cells[2]);
BOOST_REQUIRE_EQUAL(mlp.GetNumberOfCells(4), level_cells[3]);
}
BOOST_AUTO_TEST_CASE(cell_overflow_bits)
{
// bits = ceil(log2(4194304 + 1)) + ceil(log2(262144 + 1)) + ceil(log2(16384 + 1)) +
// ceil(log2(1024 + 1))
// = 23 + 19 + 15 + 11
// = 68
const size_t NUM_PARTITIONS = 4194304;
const std::vector<size_t> level_cells = {NUM_PARTITIONS, 262144, 16384, 1024};
std::vector<std::vector<CellID>> levels(level_cells.size(),
std::vector<CellID>(level_cells[0]));
std::vector<uint32_t> levels_to_num_cells(level_cells.size());
const auto set_level_cells = [&](size_t level, auto const num_cells) {
for (auto val : util::irange<size_t>(0ULL, NUM_PARTITIONS))
{
levels[level][val] = std::min(val, num_cells - 1);
}
levels_to_num_cells[level] = num_cells;
};
util::for_each_indexed(level_cells.cbegin(), level_cells.cend(), set_level_cells);
BOOST_REQUIRE_EXCEPTION(MultiLevelPartition(levels, levels_to_num_cells),
util::exception,
[](auto) { return true; });
}
BOOST_AUTO_TEST_SUITE_END()