BitMagic-C++
sample9.cpp
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1 /*
2 Copyright(c) 2002-2017 Anatoliy Kuznetsov(anatoliy_kuznetsov at yahoo.com)
3 
4 Licensed under the Apache License, Version 2.0 (the "License");
5 you may not use this file except in compliance with the License.
6 You may obtain a copy of the License at
7 
8  http://www.apache.org/licenses/LICENSE-2.0
9 
10 Unless required by applicable law or agreed to in writing, software
11 distributed under the License is distributed on an "AS IS" BASIS,
12 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 See the License for the specific language governing permissions and
14 limitations under the License.
15 
16 For more information please visit: http://bitmagic.io
17 */
18 
19 /** \example sample9.cpp
20 
21  Example demonstrates binary distance metrics. BM library can compute
22  various distances without materializing a product set.
23 
24  \sa bm::count_and
25  \sa bm::count_xor
26  \sa bm::count_sub
27  \sa bm::count_or
28  \sa bm::distance_operation
29 
30  For more information please visit: http://bmagic.sourceforge.net
31 */
32 
33 /*! \file sample9.cpp
34  \brief Example: bvector<> binary similarity / distance algorithms
35 */
36 
37 
38 #include <iostream>
39 
40 #include "bm.h"
41 #include "bmalgo.h"
42 
43 
44 using namespace std;
45 
46 
47 int main(void)
48 {
49  try
50  {
51  bm::bvector<> bv1;
52  bm::bvector<> bv2;
53 
54  bv1[10] = true;
55  bv1[100] = true;
56  bv1[10000] = true;
57 
58  bv2[10] = true;
59  bv2[100] = true;
60  bv2[20000] = true;
61  bv2[30000] = true;
62 
63  // Hamming distance:
64 
65  auto hamming = bm::count_xor(bv1, bv2);
66 
67  cout << "Hamming distance = " << hamming << endl;
68 
69  // Dice distance using basic distance functions
70 
71  double dice =
72  double(2 * bm::count_and(bv1, bv2))/double(bv1.count() + bv2.count());
73 
74  cout << "Dice distance = " << dice << endl;
75 
76 
77  // Dice distance, can be computed using "metric pipeline"
78 
80  dmd[0].metric = bm::COUNT_AND;
81  dmd[1].metric = bm::COUNT_A;
82  dmd[2].metric = bm::COUNT_B;
83 
84  bm::distance_operation(bv1, bv2, dmd, dmd+3);
85 
86  double dice_p =
87  double(2 * dmd[0].result) / double(dmd[1].result + dmd[2].result);
88 
89  cout << "Dice distance (pipeline) = " << dice_p << endl;
90  }
91  catch(std::exception& ex)
92  {
93  std::cerr << ex.what() << std::endl;
94  return 1;
95  }
96  return 0;
97 }
98 
Compressed bit-vector bvector<> container, set algebraic methods, traversal iterators.
int main(void)
Definition: sample9.cpp:47
(A & B).count()
Definition: bmalgo_impl.h:59
Algorithms for bvector<> (main include)
Distance metric descriptor, holds metric code and result.
Definition: bmalgo_impl.h:87
B.count()
Definition: bmalgo_impl.h:65
void distance_operation(const BV &bv1, const BV &bv2, distance_metric_descriptor *dmit, distance_metric_descriptor *dmit_end)
Distance computing template function.
Definition: bmalgo_impl.h:702
A.count()
Definition: bmalgo_impl.h:64
size_type count() const
population cout (count of ON bits)
Definition: bm.h:2487
bm::distance_metric_descriptor::size_type count_xor(const BV &bv1, const BV &bv2)
Computes bitcount of XOR operation of two bitsets.
Definition: bmalgo_impl.h:1018
BV::size_type count_and(const BV &bv1, const BV &bv2)
Computes bitcount of AND operation of two bitsets.
Definition: bmalgo_impl.h:986