1 /*
2 * License : The MIT License
3 * Copyright(c) 2022 olyutorskii
4 */
5
6 package io.github.olyutorskii.aletojio.rng.lcg;
7
8 import io.github.olyutorskii.aletojio.rng.RndInt32;
9
10 /**
11 * Implementation of 32bit output Linear congruential generator(LCG).
12 *
13 * <p>LCG is a commonly used random number generator in the past.
14 *
15 * <p>Recurrence relation sequences : {@code X(n+1) = (X(n) * Mul + Inc) mod Mod}
16 *
17 * <ul>
18 * <li>Mul : Multiplier
19 * <li>Inc : Increment
20 * <li>Mod : Modulus
21 * </ul>
22 *
23 * @see <a href="https://en.wikipedia.org/wiki/Linear_congruential_generator">
24 * Linear congruential generator (Wikipedia)
25 * </a>
26 */
27 public class LcgRndInt32 extends AbstractLcg implements RndInt32 {
28
29 /**
30 * Constructor.
31 *
32 * <ul>
33 * <li>Multiplier must be 1 or greatrer.
34 * <li>Increment must be 0 or greatrer.
35 * <li>Modulus must be 2 or greater.
36 * </ul>
37 *
38 * @param mulArg multiplier
39 * @param incArg increment
40 * @param modArg modulus
41 * @throws IllegalArgumentException illegal argument
42 */
43 public LcgRndInt32(long mulArg, long incArg, long modArg)
44 throws IllegalArgumentException {
45 super(mulArg, incArg, modArg);
46 return;
47 }
48
49 /**
50 * {@inheritDoc}
51 *
52 * <p>result(32bit) reflects seed[16:47]
53 *
54 * @return {@inheritDoc}
55 */
56 @Override
57 protected int seedToResult() {
58 long lVal = getSeed() >>> 16;
59 lVal &= MASK_B32;
60 int result = (int) lVal;
61 return result;
62 }
63
64 /**
65 * {@inheritDoc}
66 *
67 * @return {@inheritDoc}
68 */
69 @Override
70 public int nextInt32() {
71 int result = nextIntImpl();
72 return result;
73 }
74
75 }