onox / xoshiro

Ada/SPARK port of the xoshiro128++ and xoshiro256++ pseudo-random number generators

Xoshiro random number generators

An Ada/SPARK port of the xoshiro128++ and xoshiro256++ pseudo-random number generators.

For a SIMD implementation using SSE2 or AVX2 intrinsics, see the orka_simd crate. It is used to create tensors with some statistical distribution.

Usage

declare
    use Xoshiro256;

    RNG   : Generator;
    Value : Unsigned_64;
begin
    Reset (RNG, Seed => 1);

    Next (RNG, Value);

    Ada.Text_IO.Put_Line (To_Float (Value)'Image);
end;

Dependencies

In order to build the library, you need to have:

• An Ada 2012 compiler

• Alire package manager

License

The Ada code is licensed under the Apache License 2.0. The first line of each Ada file should contain an SPDX license identifier tag that refers to this license:

SPDX-License-Identifier: Apache-2.0

xoshiro's Issues

Ideas to try a generic version

Following our discussion on the alire-index repo I think it's worth trying to make the 128 and 256 accept any mod type that fits the requirements, e.i. 32 or 64 bits respectively.

For instance:

generic
   type Unsigned_32 is mod <>;
package Xoshiro128 with SPARK_Mode => On is
   pragma Pure;

   pragma Compile_Time_Error (Unsigned_Int'Size /= 32,
                              "Invalid mod type for Xoshiro128");

   pragma Compile_Time_Error (Unsigned_Int'Modulus /= 2**32,
                              "Invalid mod type for Xoshiro128");

This way users can instantiate the package for the type they use. Most commons will be Interfaces.Unsigned_32 or HAL.UInt32 I guess.
Same thing for Xoshiro256.