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108 lines (101 loc) · 6.47 KB
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/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
#include <nanobind/nanobind.h>
#include <nanobind/stl/string.h>
#include "count_min.hpp"
#include "common_defs.hpp"
namespace nb = nanobind;
template<typename W>
void bind_count_min_sketch(nb::module_ &m, const char* name) {
using namespace datasketches;
nb::class_<count_min_sketch<W>>(m, name)
.def(nb::init<uint8_t, uint32_t, uint64_t>(), nb::arg("num_hashes"), nb::arg("num_buckets"), nb::arg("seed")=DEFAULT_SEED,
"Creates an instance of a CountMin sketch\n\n"
":param num_hashes: Number of rows in the sketch\n:type num_hashes: int\n"
":param num_buckets: Number of columns in the sketch\n:type num_buckets: int\n"
":param seed: Hash seed to use\n:type seed: int, optional"
)
// using nun_hashes (rows), num_buckets (columns), and hash seed `seed`.)
.def("__copy__", [](const count_min_sketch<W>& sk){ return count_min_sketch<W>(sk); })
.def_static("suggest_num_buckets", &count_min_sketch<W>::suggest_num_buckets, nb::arg("relative_error"),
"Suggests the number of buckets needed to achieve an accuracy within the provided "
"relative_error. For example, when relative_error = 0.05, the returned frequency estimates "
"satisfy the 'relative_error' guarantee that never overestimates the weights but may "
"underestimate the weights by 5% of the total weight in the sketch. "
"Returns the number of hash buckets at every level of the sketch required in order to obtain "
"the specified relative error.")
.def_static("suggest_num_hashes", &count_min_sketch<W>::suggest_num_hashes, nb::arg("confidence"),
"Suggests the number of hashes needed to achieve the provided confidence. For example, "
"with 95% confidence, frequency estimates satisfy the 'relative_error' guarantee. "
"Returns the number of hash functions that are required in order to achieve the specified "
"confidence of the sketch. confidence = 1 - delta, with delta denoting the sketch failure probability.")
.def("__str__", [](const count_min_sketch<W>& sk) { return sk.to_string(); },
"Produces a string summary of the sketch")
.def("to_string", &count_min_sketch<W>::to_string,
"Produces a string summary of the sketch")
.def("is_empty", &count_min_sketch<W>::is_empty,
"Returns True if the sketch has seen no items, otherwise False")
.def_prop_ro("num_hashes", &count_min_sketch<W>::get_num_hashes,
"The configured number of hashes for the sketch")
.def_prop_ro("num_buckets", &count_min_sketch<W>::get_num_buckets,
"The configured number of buckets for the sketch")
.def_prop_ro("seed", &count_min_sketch<W>::get_seed,
"The base hash seed for the sketch")
.def("get_relative_error", &count_min_sketch<W>::get_relative_error,
"Returns the maximum permissible error for any frequency estimate query")
.def_prop_ro("total_weight", &count_min_sketch<W>::get_total_weight,
"The total weight currently inserted into the stream")
.def("update", static_cast<void (count_min_sketch<W>::*)(int64_t, W)>(&count_min_sketch<W>::update), nb::arg("item"), nb::arg("weight")=1.0,
"Updates the sketch with the given 64-bit integer value")
.def("update", static_cast<void (count_min_sketch<W>::*)(const std::string&, W)>(&count_min_sketch<W>::update), nb::arg("item"), nb::arg("weight")=1.0,
"Updates the sketch with the given string")
.def("get_estimate", static_cast<W (count_min_sketch<W>::*)(int64_t) const>(&count_min_sketch<W>::get_estimate), nb::arg("item"),
"Returns an estimate of the frequency of the provided 64-bit integer value")
.def("get_estimate", static_cast<W (count_min_sketch<W>::*)(const std::string&) const>(&count_min_sketch<W>::get_estimate), nb::arg("item"),
"Returns an estimate of the frequency of the provided string")
.def("get_upper_bound", static_cast<W (count_min_sketch<W>::*)(int64_t) const>(&count_min_sketch<W>::get_upper_bound), nb::arg("item"),
"Returns an upper bound on the estimate for the given 64-bit integer value")
.def("get_upper_bound", static_cast<W (count_min_sketch<W>::*)(const std::string&) const>(&count_min_sketch<W>::get_upper_bound), nb::arg("item"),
"Returns an upper bound on the estimate for the provided string")
.def("get_lower_bound", static_cast<W (count_min_sketch<W>::*)(int64_t) const>(&count_min_sketch<W>::get_lower_bound), nb::arg("item"),
"Returns a lower bound on the estimate for the given 64-bit integer value")
.def("get_lower_bound", static_cast<W (count_min_sketch<W>::*)(const std::string&) const>(&count_min_sketch<W>::get_lower_bound), nb::arg("item"),
"Returns a lower bound on the estimate for the provided string")
.def("merge", &count_min_sketch<W>::merge, nb::arg("other"),
"Merges the provided other sketch into this one")
.def("get_serialized_size_bytes", &count_min_sketch<W>::get_serialized_size_bytes,
"Returns the size in bytes of the serialized image of the sketch")
.def(
"serialize",
[](const count_min_sketch<W>& sk) {
auto bytes = sk.serialize();
return nb::bytes(reinterpret_cast<const char*>(bytes.data()), bytes.size());
},
"Serializes the sketch into a bytes object"
)
.def_static(
"deserialize",
[](const nb::bytes& bytes) { return count_min_sketch<W>::deserialize(bytes.c_str(), bytes.size()); },
nb::arg("bytes"),
"Reads a bytes object and returns the corresponding count_min_sketch"
);
}
void init_count_min(nb::module_ &m) {
bind_count_min_sketch<double>(m, "count_min_sketch");
}