1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
|
/*
* DSI utilities
*
* Copyright (C) 2010-2023 Sebastiano Vigna
*
* This program and the accompanying materials are made available under the
* terms of the GNU Lesser General Public License v2.1 or later,
* which is available at
* http://www.gnu.org/licenses/old-licenses/lgpl-2.1-standalone.html,
* or the Apache Software License 2.0, which is available at
* https://www.apache.org/licenses/LICENSE-2.0.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE.
*
* SPDX-License-Identifier: LGPL-2.1-or-later OR Apache-2.0
*/
package it.unimi.dsi.bits;
import static org.junit.Assert.assertEquals;
import org.junit.Test;
import it.unimi.dsi.util.SplitMix64RandomGenerator;
public class FastTest {
@Test
public void testCeilLog2() {
for(int i = 1; i < 1000; i++) assertEquals((int)Math.ceil(Math.log(i) / Math.log(2)), Fast.ceilLog2(i));
}
@Test
public void testLength() {
assertEquals(1, Fast.length(0));
assertEquals(1, Fast.length(0L));
for(int i = 1; i < 100; i++) assertEquals(Fast.mostSignificantBit(i) + 1, Fast.length(i));
for(long i = 1; i < 100; i++) assertEquals(Fast.mostSignificantBit(i) + 1, Fast.length(i));
}
@Test
public void testMostSignificantBitInt() {
assertEquals(-1, Fast.mostSignificantBit(0));
for(int i = 0; i < 32; i++) {
assertEquals(i, Fast.mostSignificantBit(1L << i));
assertEquals(i, Fast.mostSignificantBit(1L << i | 1));
assertEquals(i, Fast.mostSignificantBit(1L << i));
assertEquals(i, Fast.mostSignificantBit(1L << i | 1));
}
}
@Test
public void testMostSignificantBitLong() {
assertEquals(-1, Fast.mostSignificantBit(0));
for(int i = 0; i < 64; i++) {
assertEquals(i, Fast.mostSignificantBit(1L << i));
assertEquals(i, Fast.mostSignificantBit(1L << i | 1));
assertEquals(i, Fast.mostSignificantBit(1L << i));
assertEquals(i, Fast.mostSignificantBit(1L << i | 1));
}
}
@Test
public void testSelect2() {
assertEquals(0, Fast.select(1, 0));
for(int i = 0; i < 64; i++) assertEquals(i, Fast.select(0xFFFFFFFFFFFFFFFFL, i));
for(int i = 1; i < 32; i++) assertEquals(2 * i + 1, Fast.select(0xAAAAAAAAAAAAAAAAL, i));
final SplitMix64RandomGenerator r = new SplitMix64RandomGenerator(0);
for(int i = 100000; i-- != 0;) {
final long x = r.nextLong();
final int count = Long.bitCount(x);
for(int rank = count; rank-- != 0;) assertEquals(Fast.select(x, rank), Fast.select(x, rank));
}
}
@Test
public void testInt2Nat() {
assertEquals(Integer.MAX_VALUE, Fast.int2nat(Integer.MIN_VALUE / 2));
assertEquals(Integer.MAX_VALUE - 2, Fast.int2nat(Integer.MIN_VALUE / 2 + 1));
assertEquals(Integer.MAX_VALUE - 1, Fast.int2nat(Integer.MAX_VALUE / 2));
for(int i = 0; i < 16; i++) assertEquals(2*i, Fast.int2nat(i));
for(int i = -16; i < 0; i++) assertEquals(-2*i-1, Fast.int2nat(i));
assertEquals(Long.MAX_VALUE, Fast.int2nat(Long.MIN_VALUE / 2));
assertEquals(Long.MAX_VALUE - 2, Fast.int2nat(Long.MIN_VALUE / 2 + 1));
assertEquals(Long.MAX_VALUE - 1, Fast.int2nat(Long.MAX_VALUE / 2));
for(int i = 0; i < 16; i++) assertEquals(2L*i, Fast.int2nat(i));
for(int i = -16; i < 0; i++) assertEquals(-2L*i-1, Fast.int2nat(i));
}
@Test
public void testNat2Int() {
assertEquals(Integer.MIN_VALUE / 2, Fast.nat2int(Integer.MAX_VALUE));
assertEquals(Integer.MIN_VALUE / 2 + 1, Fast.nat2int(Integer.MAX_VALUE - 2));
assertEquals(Integer.MAX_VALUE / 2, Fast.nat2int(Integer.MAX_VALUE - 1));
for(int i = 0; i < 16; i++) assertEquals(i, Fast.nat2int(2*i));
for(int i = -16; i < 0; i++) assertEquals(i, Fast.nat2int(-2*i-1));
assertEquals(Long.MIN_VALUE / 2 + 1, Fast.nat2int(Long.MAX_VALUE - 2));
assertEquals(Long.MIN_VALUE / 2, Fast.nat2int(Long.MAX_VALUE));
assertEquals(Long.MAX_VALUE / 2, Fast.nat2int(Long.MAX_VALUE - 1));
for(int i = 0; i < 16; i++) assertEquals(i, Fast.nat2int(2L*i));
for(int i = -16; i < 0; i++) assertEquals(i, Fast.nat2int(-2L*i-1));
}
}
|
