sample16.cpp
Go to the documentation of this file.
/*
Copyright(c) 2002-2017 Anatoliy Kuznetsov(anatoliy_kuznetsov at yahoo.com)
Licensed 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.
For more information please visit: http://bitmagic.io
*/
/** \example sample16.cpp
Example for finding first and last bits in bit-vector (dynamic range).
Ranges of bit-vectors can be used to find probability of intersection.
For instance, in some corner cases AND product can be predicted empty if vectors
belong to different ranges.
@sa bm::aggregator
*/
/*! \file sample16.cpp
\brief Example: how to use bm::aggregator<> for logical operations
bm::aggregator<> uses cache blocking techniques and bandwidth optimizations
to do logical operations (OR, AND, AND-SUB) faster, than if we do it by
combining bit-vectors one by one, sequentially.
*/
#include <stdlib.h>
#include <iostream>
#include <vector>
#include <memory>
#include "bm.h"
#include "bmaggregator.h"
#include "bmundef.h" /* clear the pre-proc defines from BM */
// Utility template function used to print container
template<class T> void PrintContainer(T first, T last)
{
if (first == last)
std::cout << "<EMPTY SET>";
else
for (; first != last; ++first)
std::cout << *first << ";";
std::cout << std::endl;
}
const unsigned max_vectors = 10;
int main(void)
{
try
{
// declare standalone aggregator for logical operations
bm::aggregator<bm::bvector<> > agg;
std::cout << "AGRUMENT (GROUP 0) SETS:" << std::endl;
// make vector of bit-vectors, set some bits
std::vector<std::unique_ptr<bm::bvector<> > > vect;
for (unsigned i = 0; i < max_vectors; ++i)
{
std::unique_ptr<bm::bvector<>> bv(new bm::bvector<>());
bv->set(i);
bv->set(i+1);
bv->set(10000);
bv->set(20000);
PrintContainer(bv->first(), bv->end());
bv->optimize();
vect.push_back(std::move(bv));
}
std::cout << std::endl;
try
{
// in a loop we add all agruments to the aggregator
// (aggregator does not take ownership of pointers it receives)
//
for (unsigned i = 0; i < vect.size(); ++i)
{
agg.add(vect[i].get());
}
bm::bvector<> bv_res; // target vector for aggregation
agg.combine_or(bv_res); // perform logical OR on a vector group
std::cout << "OR:" << std::endl;
PrintContainer(bv_res.first(), bv_res.end()); // 0, 1, 2, 3, 4... 10000, 20000
// since we did not call bm::aggregator::reset() the vector group
// still remains attached
std::cout << "AND:" << std::endl;
agg.combine_and(bv_res); // AND on the same vector group
PrintContainer(bv_res.first(), bv_res.end()); // 10000, 20000
agg.reset(); // reset the aggregator
// fused logical AND MINUS example
// AND(vector-group-0) SUBstract (AND NOT) vector-group-1
for (unsigned i = 0; i < vect.size(); ++i)
{
const unsigned group0 = 0; // vector group 0
agg.add(vect[i].get(), group0);
}
// Note that we do not set vector group 1 yet, so operation just
// runs as a regular AND MINUS an empty-set
agg.combine_and_sub(bv_res); // AND-SUB vector group1 and group2
std::cout << "AND-SUB(empty):" << std::endl;
PrintContainer(bv_res.first(), bv_res.end()); // 10000, 20000
bm::bvector<> bv_not { 10, 10000 };
agg.add(&bv_not, 1); // add to vector-group-1
agg.combine_and_sub(bv_res); // AND-SUB vector group0 minus group1
std::cout << "AND-SUB:" << std::endl;
PrintContainer(bv_res.first(), bv_res.end()); // 20000
agg.reset();
}
catch(std::exception& ex)
{
std::cerr << ex.what() << std::endl;
agg.reset(); // reset
throw;
}
}
catch(std::exception& ex)
{
std::cerr << ex.what() << std::endl;
return 1;
}
return 0;
}
bm.h
Compressed bit-vector bvector<> container, set algebraic methods, traversal iterators.
bmaggregator.h
Algorithms for fast aggregation of N bvectors.
bmundef.h
pre-processor un-defines to avoid global space pollution (internal)
bm::aggregator
Algorithms for fast aggregation of a group of bit-vectors.
Definition bmaggregator.h:122
bm::aggregator::combine_and_sub
bool combine_and_sub(bvector_type &bv_target)
Aggregate added group of vectors using fused logical AND-SUB Operation does NOT perform an explicit r...
Definition bmaggregator.h:1044
bm::aggregator::reset
void reset()
Reset aggregate groups, forget all attached vectors.
Definition bmaggregator.h:941
bm::aggregator::combine_or
void combine_or(bvector_type &bv_target)
Aggregate added group of vectors using logical OR Operation does NOT perform an explicit reset of arg...
Definition bmaggregator.h:1021
bm::aggregator::combine_and
void combine_and(bvector_type &bv_target)
Aggregate added group of vectors using logical AND Operation does NOT perform an explicit reset of ar...
Definition bmaggregator.h:1030
bm::aggregator::add
size_t add(const bvector_type *bv, unsigned agr_group=0)
Attach source bit-vector to a argument group (0 or 1).
Definition bmaggregator.h:1013
bm::bvector
Bitvector Bit-vector container with runtime compression of bits.
Definition bm.h:115
bm::bvector::first
enumerator first() const
Returns enumerator pointing on the first non-zero bit.
Definition bm.h:1871
bm::bvector::end
enumerator end() const
Returns enumerator pointing on the next bit after the last.
Definition bm.h:1877
max_vectors
const unsigned max_vectors
Definition sample16.cpp:58
main
int main(void)
Definition sample1.cpp:43
PrintContainer
void PrintContainer(T first, T last)
Definition sample7.cpp:62