philox4x32x10¶
The Philox4x32x10 counter-based pseudorandom number generator.
Description
The Philox4x32x10 engine is a keyed family of generator of counter-based BRNG. The state consists of 128-bit integer counter \(c\) and two 32-bits keys \(k_0\) and \(k_1\).
Generation algorithm
The generator has 32-bit integer output obtained in the following way [Salmon11]:
\(c_n=c_{n-1} + 1\)
- \(\omega_n = f(c_n)\), where \(f\) is a function that takes 128-bit argument and returns a 128-bit number. The returned number is obtained as follows:
2.1. The argument \(c\) is interpreted as four 32-bit numbers \(c = \overline{L_1 R_1 L_0 R_0}\), where \(\overline{A B C D} = A \cdot 2^{96} + B \cdot 2^{64} + C \cdot 2^{32} + D\), put \(k_0^0 =k_0, k_1^0=k_1\).
2.2. The following recurrence is calculated:
\(L_1^{i+1} =mullo(R_1^i, 0xD2511F53)\)
\(R_1^{i+1} =mulhi(R_0^i, 0xCD9E8D57) \oplus k_0^i \oplus L_0^i\)
\(L_0^{i+1} =mullo(R_0^i, 0xCD9E8D57)\)
\(R_0^{i+1} =mulhi(R_1^i, 0xD2511F53) \oplus k_1^i \oplus L_1^i\)
\(k_0^{i+1} =k_0^i + 0xBB67AE85\)
\(k_1^{i+1} =k_1^i + 0x9E3779B9\), where \(mulhi(a, b)\) and \(mullo(a, b)\) are high and low parts of the \(a \cdot b\) product respectively.
2.3. Put \(f(c) = \overline{L_1^N R_1^N L_0^N R_0^N}\), where \(N = 10\)
Integer output: \(r_{4n + k} = \omega_n(k)\), where \(\omega_n(k)\) is the k-th 32-bit integer in quadruple \(\omega_n, k = 0, 1, 2, 3\)
Real output: \(u_n=(int)r_n / 2^{32} + 1/2\)
class philox4x32x10¶
Syntax
namespace oneapi::mkl::rng {
class philox4x32x10 {
public:
static constexpr std::uint64_t default_seed = 0;
philox4x32x10(sycl::queue queue, std::uint64_t seed = default_seed);
philox4x32x10(sycl::queue queue, std::initializer_list<std::uint64_t> seed);
philox4x32x10(const philox4x32x10& other);
philox4x32x10(philox4x32x10&& other);
philox4x32x10& operator=(const philox4x32x10& other);
philox4x32x10& operator=(philox4x32x10&& other);
~philox4x32x10();
};
}
Class Members
Routine |
Description |
|---|---|
philox4x32x10(sycl::queue queue, std::uint64_t seed = default_seed) |
Constructor for common seed initialization of the engine |
philox4x32x10(sycl::queue queue, std::initializer_list<std::uint64_t> seed) |
Constructor for extended seed initialization of the engine |
Copy constructor |
|
Move constructor |
|
Copy assignment operator |
|
Move assignment operator |
Constructors
philox4x32x10::philox4x32x10(sycl::queue queue, std::uint64_t seed = default_seed)
Input Parameters
- queue
Valid
sycl::queueobject, calls of the oneapi::mkl::rng::generate() routine submits kernels in this queue to obtain random numbers from a given engine.- seed
The initial conditions of the generator state, assume \(k = seed, c = 0\), where \(k\) is a 64-bit key, \(c\) is a 128-bit counter.
philox4x32x10::philox4x32x10(sycl::queue queue, std::initializer_list<std::uint64_t> seed)
Input Parameters
- queue
Valid
sycl::queueobject, calls of the oneapi::mkl::rng::generate() routine submits kernels in this queue to obtain random numbers from a given engine.- seed
The initial conditions of the generator state, assume if \(n = 0: k = 0, c = 0\)
if \(n = 1: k = seed[0], c = 0\)
if \(n = 2: k = seed[0], c = seed[1]\)
if \(n = 3: k = seed[0], c = seed[1] + seed[2] \cdot 2^{64}\)
for \(n > 3\) following arguments are ignored
philox4x32x10::philox4x32x10(const philox4x32x10& other)
Input Parameters
- other
Valid
philox4x32x10object. Thequeueand state of the other engine is copied and applied to the current engine.
philox4x32x10::philox4x32x10(philox4x32x10&& other)
Input Parameters
- other
Valid
philox4x32x10r-value object. Thequeueand state of the other engine is moved to the current engine.
philox4x32x10::philox4x32x10& operator=(const philox4x32x10& other)
Input Parameters
- other
Valid
philox4x32x10object. Thequeueand state of the other engine is copied and applied to the current engine.
philox4x32x10::philox4x32x10& operator=(philox4x32x10&& other)
Input Parameters
- other
Valid
philox4x32x10r-value object. Thequeueand state of the other engine is moved to the current engine.
Parent topic: Engines (Basic Random Number Generators)