RFR: 8302987: Add uniform and spatially equidistributed bounded float/double streams to RandomGenerator

[Raffaello Giulietti]

On Wed, 22 Feb 2023 15:23:13 GMT, Raffaello Giulietti <rgiulietti at openjdk.org> wrote:

> The `default` method `nextDouble(double origin, double bound)` in `java.util.random.RandomGenerator` aims at generating a uniformly and spatially equidistributed random `double` in the left-closed and right-open range [`origin`, `bound`). It does so by applying the affine transform `origin + (bound - origin) * r` to a uniformly and spatially equidistributed random `double` `r` in the range [0, 1).
> 
> Since floating-point arithmetic suffers from small but noticeable rounding errors, this ends up slightly deforming the distribution of `r` when applying the affine transform.

A similar implementation for `float`s will be added once this PR has elicited some interest and the algorithm has undergone a first review.

A CSR and tests will then be added as well.

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PR: https://git.openjdk.org/jdk/pull/12719