kpermute/com.eignex.kpermute/ArrayLongPermutation

ArrayLongPermutation

class ArrayLongPermutation(val size: Long, rng: Random) : LongPermutation(source)

Finite in-memory long permutation backed by a LongArray lookup table.

Builds a random bijection over [0, size) by shuffling the identity mapping and precomputing the inverse. Encode and decode are O(1) array lookups.

Parameters

rng

Random generator used to create the shuffled mapping.

Constructors

ArrayLongPermutation

constructor(size: Long, rng: Random)

Properties

size

open override val size: Long

Size of the permutation domain; valid inputs are [0, size).

Functions

decode

open fun decode(encoded: Long): Long

Decodes a previously encoded long back to its original value.

decodeUnchecked

open override fun decodeUnchecked(encoded: Long): Long

Decodes a previously encoded value without range checks.

encode

open fun encode(value: Long): Long

Encodes a long in the permutation domain into its permuted value.

encodeUnchecked

open override fun encodeUnchecked(value: Long): Long

Encodes a value without range checks.

iterator

open override fun iterator(offset: Long): LongIterator

Returns an iterator over encode(i) for indices in [offset, size).

open operator override fun iterator(): LongIterator

Returns an iterator over encode(i) for all i in [0, size) for finite domains, or over the full 64-bit space when size == -1L.

range

fun LongPermutation.range(range: LongRange): LongPermutation

Returns a view of this permutation that operates on range instead of [0, size). Only valid for finite domains where range.count() == size.

toString

open override fun toString(): String