Random\Engine\Xoshiro256StarStar
PHP Manual

Random\Engine\Xoshiro256StarStar::jumpLong

Efficiently move the engine ahead by 2^192 steps

Description

public void Random\Engine\Xoshiro256StarStar::jumpLong()

Moves the algorithm’s state ahead by 2192 steps, as if Random\Engine\Xoshiro256StarStar::generate was called 2192 times.

The purpose of a long jump is to facilitate the creation of a new Random\Engine\Xoshiro256StarStar engine from an existing seeded Random\Engine\Xoshiro256StarStar engine. The seeded engine acts as a blueprint, which can be cloned and repeatedly jumped to create 264 non-overlapping sequences with 2192 values each.

Long jumping may be combined with Random\Engine\Xoshiro256StarStar::jumping to further split each of the 264 sequences generated by long jumping, into 264 sequences of 2128 values each.

Parameters

This function has no parameters.

Return Values

No value is returned.

Examples

Example #1 Random\Engine\Xoshiro256StarStar::jumpLong example

<?php
$blueprintRng = new \Random\Engine\Xoshiro256StarStar(0);

// Each parent engine will have its own chunk of 2**192 values.
$parent1 = clone $blueprintRng;
$blueprintRng->jumpLong();

$parent2 = clone $blueprintRng;
$blueprintRng->jumpLong();

// Each of the child engines will have its own chunk of 2**128 values
// taken from their parent engine’s chunk of 2**192 values.
$child1a = clone $parent1;
$parent1->jump();
$child1b = clone $parent1;
$parent1->jump();

$child2a = clone $parent2;
$parent2->jump();
$child2b = clone $parent2;
$parent2->jump();

echo "Child 1A: ", bin2hex($child1a->generate()), "\n";
echo "Child 1B: ", bin2hex($child1b->generate()), "\n";
echo "Child 2A: ", bin2hex($child2a->generate()), "\n";
echo "Child 2B: ", bin2hex($child2b->generate()), "\n";
?>

The above example will output:

Child 1A: b4f275cb365fec99
Child 1B: 2cd646c8ed156237
Child 2A: eb3729a722a504e7
Child 2B: d4208dc85bdd6dc3

See Also

  • Random\Engine\Xoshiro256StarStar::jump