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hilbert encode function added

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This commit is contained in:
Artem Mustafin 2024-02-19 20:21:52 +00:00
parent b2b9f5e53a
commit 9a8101ebdc
1 changed files with 75 additions and 11 deletions
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86
src/Functions/hilbertEncode.cpp
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@ -1,21 +1,80 @@
#include <Functions/IFunction.h>
#include <Functions/FunctionFactory.h>
#include <Columns/ColumnsNumber.h>
#include <Columns/ColumnConst.h>
#include <Columns/ColumnTuple.h>
#include <Columns/ColumnsNumber.h>
#include <Common/BitHelpers.h>
#include <Functions/FunctionFactory.h>
#include <Functions/FunctionSpaceFillingCurveEncode.h>
#include <Functions/IFunction.h>
#include <Functions/PerformanceAdaptors.h>
#include <limits>
namespace DB
{
namespace ErrorCodes
{
extern const int ILLEGAL_TYPE_OF_ARGUMENT;
extern const int ARGUMENT_OUT_OF_BOUND;
extern const int TOO_FEW_ARGUMENTS_FOR_FUNCTION;
}
class FunctionHilbertEncode2DWIthLookupTableImpl {
public:
static UInt64 encode(UInt64 x, UInt64 y) {
const auto leading_zeros_count = getLeadingZeroBits(x | y);
const auto used_bits = std::numeric_limits<UInt64>::digits - leading_zeros_count;
UInt8 remaind_shift = BIT_STEP - used_bits % BIT_STEP;
if (remaind_shift == BIT_STEP)
remaind_shift = 0;
x <<= remaind_shift;
y <<= remaind_shift;
UInt8 current_state = 0;
UInt64 hilbert_code = 0;
Int8 current_shift = used_bits + remaind_shift - BIT_STEP;
while (current_shift > 0)
{
const UInt8 x_bits = (x >> current_shift) & STEP_MASK;
const UInt8 y_bits = (y >> current_shift) & STEP_MASK;
const auto hilbert_bits = getCodeAndUpdateState(x_bits, y_bits, current_state);
const UInt8 hilbert_code_shift = static_cast<UInt8>(current_shift) << 1;
hilbert_code |= (hilbert_bits << hilbert_code_shift);
current_shift -= BIT_STEP;
}
hilbert_code >>= (remaind_shift << 1);
return hilbert_code;
}
private:
// LOOKUP_TABLE[SSXXXYYY] = SSHHHHHH]
// where SS - 2 bits for state, XXX - 3 bits of x, YYY - 3 bits of y
static UInt8 getCodeAndUpdateState(UInt8 x_bits, UInt8 y_bits, UInt8& state) {
const UInt8 table_index = state | (x_bits << BIT_STEP) | y_bits;
const auto table_code = LOOKUP_TABLE[table_index];
state = table_code & STATE_MASK;
return table_code & HILBERT_MASK;
}
constexpr static UInt8 BIT_STEP = 3;
constexpr static UInt8 STEP_MASK = (1 << BIT_STEP) - 1;
constexpr static UInt8 HILBERT_MASK = (1 << (BIT_STEP << 1)) - 1;
constexpr static UInt8 STATE_MASK = static_cast<UInt8>(-1) - HILBERT_MASK;
constexpr static UInt8 LOOKUP_TABLE[256] = {
64, 1, 206, 79, 16, 211, 84, 21, 131, 2, 205, 140, 81, 82, 151, 22, 4, 199, 8, 203, 158,
157, 88, 25, 69, 70, 73, 74, 31, 220, 155, 26, 186, 185, 182, 181, 32, 227, 100, 37, 59,
248, 55, 244, 97, 98, 167, 38, 124, 61, 242, 115, 174, 173, 104, 41, 191, 62, 241, 176, 47,
236, 171, 42, 0, 195, 68, 5, 250, 123, 60, 255, 65, 66, 135, 6, 249, 184, 125, 126, 142,
141, 72, 9, 246, 119, 178, 177, 15, 204, 139, 10, 245, 180, 51, 240, 80, 17, 222, 95, 96,
33, 238, 111, 147, 18, 221, 156, 163, 34, 237, 172, 20, 215, 24, 219, 36, 231, 40, 235, 85,
86, 89, 90, 101, 102, 105, 106, 170, 169, 166, 165, 154, 153, 150, 149, 43, 232, 39, 228,
27, 216, 23, 212, 108, 45, 226, 99, 92, 29, 210, 83, 175, 46, 225, 160, 159, 30, 209, 144,
48, 243, 116, 53, 202, 75, 12, 207, 113, 114, 183, 54, 201, 136, 77, 78, 190, 189, 120, 57,
198, 71, 130, 129, 63, 252, 187, 58, 197, 132, 3, 192, 234, 107, 44, 239, 112, 49, 254,
127, 233, 168, 109, 110, 179, 50, 253, 188, 230, 103, 162, 161, 52, 247, 56, 251, 229, 164,
35, 224, 117, 118, 121, 122, 218, 91, 28, 223, 138, 137, 134, 133, 217, 152, 93, 94, 11,
200, 7, 196, 214, 87, 146, 145, 76, 13, 194, 67, 213, 148, 19, 208, 143, 14, 193, 128,
};
};
class FunctionHilbertEncode : public FunctionSpaceFillingCurveEncode
@ -69,14 +128,19 @@ public:
const ColumnPtr & col0 = non_const_arguments[0 + vector_start_index].column;
if (num_dimensions == 1) {
for (size_t i = 0; i < input_rows_count; i++)
for (size_t i = 0; i < input_rows_count; ++i)
{
vec_res[i] = col0->getUInt(i);
}
return col_res;
}
return nullptr;
const ColumnPtr & col1 = non_const_arguments[1 + vector_start_index].column;
for (size_t i = 0; i < input_rows_count; ++i)
{
vec_res[i] = FunctionHilbertEncode2DWIthLookupTableImpl::encode(col0->getUInt(i), col1->getUInt(i));
}
return col_res;
}
};