Package io.github.olyutorskii.aletojio.rng.dull

Class StepSequence

java.lang.Object

io.github.olyutorskii.aletojio.rng.dull.StepSequence

All Implemented Interfaces:

RndInt32

public class StepSequence
extends Object
implements RndInt32

Step progression sequence generator.

X(n) = start + step * n

If a suitable step is selected, it can be compromised as a quasi-random number generator.

Using large prime numbers other than 2 for step would give a long period.

Integer.MAX_VALUE is followed by Integer.MIN_VALUE.

See Also:

• Low-discrepancy sequence (Wikipedia)

Field Summary

Fields

Modifier and Type	Field	Description
static final int	PRIME_STEP	Prime number near equal golden ratio of Integer.MAX.

Constructor Summary

Constructors

Constructor	Description
StepSequence(int start, int step)	Constructor.

Method Summary

Modifier and Type	Method	Description
static StepSequence	createCounter()	Create simple counter.
static StepSequence	createQuasiRandom()	Create Quasi-random generator.
int	nextInt32()	Return next random number as 32bit int with random sign-bit.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

PRIME_STEP

public static final int PRIME_STEP

Prime number near equal golden ratio of Integer.MAX.

Using this number for step yields sparse results that are hard to approximate with rational numbers.

Ref : Integer.MAX * (3-SQRT(5)) = 1640531525

See Also:

• Golden ratio (Wikipedia)
• Low-discrepancy sequence (Wikipedia)
• Constant Field Values

Constructor Details

StepSequence

public StepSequence(int start,
 int step)

Constructor.

output sequence will be {start, start+step, start+step*2, start+step*3, ...}

Overflow is ignored.

Parameters:

start - start value

step - step value

Method Details

createCounter

public static StepSequence createCounter()

Create simple counter.

{0, 1, 2, ...}

Returns:

counter

createQuasiRandom

public static StepSequence createQuasiRandom()

Create Quasi-random generator.

Quasi-random generator outputs extremely uniform random numbers.

Returns:

random generator

See Also:

• Low-discrepancy sequence (Wikipedia)

nextInt32

public int nextInt32()

Return next random number as 32bit int with random sign-bit.

Specified by:

nextInt32 in interface RndInt32

Returns:

random number