Currently the [rng] sampler package can only shuffle primitive int[] arrays:
o.a.c.rng.sampling.PermutationSampler:
public static void shuffle(UniformRandomProvider rng, int[] list)
public static void shuffle(UniformRandomProvider rng,
int[] list,
int start,
boolean towardHead)
I would like to be able to shuffle other arrays such as double[].
There is actually this functionality in [Lang] o.a.c.lang3.ArrayUtils.
However it uses java.util.Random for the random source, and does not
support a sub-range, e.g.
public static void shuffle(final byte[] array)
public static void shuffle(final byte[] array, final Random random)
I suggest an API that requires UniformRandomProvider and can handle
sub-ranges as:
public static void shuffle(UniformRandomProvider rng, int[] data);
public static void shuffle(UniformRandomProvider rng, int[] data, int
from, int to);
Or (similar to java.util.Arrays.copyOfRange):
public static void shuffleOfRange(UniformRandomProvider rng, int[]
data, int from, int to);
This can be repeated for all 8 primitive types and generic type T.
I suggest putting this in the sampling package but under what class?
Note that all public class names in the sampling package currently end
in Sampler. I would suggest ArraySampler.
Note there is currently a ListSampler which has generic methods to
return List<T> samples from a list, and shuffle lists. So adding
ArraySampler with only shuffling would be missing equivalent sample
methods. Consistency would require adding 8 variations of sample and a
generic one:
public static double[] sample(UniformRandomProvider rng,
double[] array,
int k) {
public static <T> T[] sample(UniformRandomProvider rng,
T[] array,
int k)
I have no use case for this but can add it for completeness.
Alex
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