Package jline.solvers.ldes.handlers

Class LdesStreamSeeds

java.lang.Object
jline.solvers.ldes.handlers.LdesStreamSeeds
public final class LdesStreamSeeds extends Object
The six MRG32k3a seeds of an LDES stream, derived from (run seed, stream offset) by splitmix64.

The offset only NAMES a stream. It used to be added to the seed directly, {seed+off, ..., seed+off+5}, and that is wrong for MRG32k3a: its two recurrences are linear, so streams whose seed vectors are equally spaced are linearly dependent, the draws of offsets o, o+10 and o+20 satisfying u1 - 2*u2 + u3 = 0 (mod 1) draw for draw. Sibling stations sit at exactly such offsets, so the branches of a 3-way fork drew in lockstep and E[max] of three Exp(1) branches came out 1.845 against 11/6.

The C++ engine's rng::SeedHash (cpp/include/line/util/rng_ssj.h) is the same function draw for draw, which is what keeps the two flat engines on one sample path. The arithmetic is unsigned 64-bit: Java's wrapping multiplication and addition agree with C++'s, the shifts are logical (>>>) and the reduction uses Long.remainderUnsigned(long, long).

  • Method Summary

    Modifier and Type
    Method
    Description
    static long[]
    mrg32k3a(long seed, long offset)
    The seed vector of the stream named offset in a run seeded seed: the first three in [1, m1), the last three in [1, m2), so neither component can start from the all-zero state SSJ rejects.

    Methods inherited from class java.lang.Object

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

  • Method Details

    • mrg32k3a

      public static long[] mrg32k3a(long seed, long offset)
      The seed vector of the stream named offset in a run seeded seed: the first three in [1, m1), the last three in [1, m2), so neither component can start from the all-zero state SSJ rejects.
      Parameters:
      seed - the run seed
      offset - the stream's offset
      Returns:
      the six seeds, for MRG32k3a.setSeed