.. index:: fast_random .. _fast_random/0:

.. rst-class:: right

object

fast_random

Fast portable random number generator predicates. Core predicates originally written by Richard O'Keefe. Based on algorithm AS 183 from Applied Statistics.

| Availability: | logtalk_load(random(loader))

| Author: Paulo Moura | Version: 2:11:0 | Date: 2023-11-24

| Compilation flags: | static, context_switching_calls

| Implements: | public :ref:`pseudo_random_protocol <pseudo_random_protocol/0>` | Uses: | :ref:`list <list/0>`

| Remarks:

• Single random number generator: This object provides a faster version of the random library object but does not support being extended to define multiple random number generators.
• Randomness: Loading this object always initializes the random generator seed to the same value, thus providing a pseudo random number generator. The randomize/1 predicate can be used to initialize the seed with a random value.

| Inherited public predicates: |  :ref:`random_protocol/0::between/3`  :ref:`random_protocol/0::enumerate/2`  :ref:`pseudo_random_protocol/0::get_seed/1`  :ref:`random_protocol/0::maybe/0`  :ref:`random_protocol/0::maybe/1`  :ref:`random_protocol/0::maybe/2`  :ref:`random_protocol/0::maybe_call/1`  :ref:`random_protocol/0::maybe_call/2`  :ref:`random_protocol/0::member/2`  :ref:`random_protocol/0::permutation/2`  :ref:`random_protocol/0::random/1`  :ref:`random_protocol/0::random/3`  :ref:`random_protocol/0::randseq/4`  :ref:`random_protocol/0::randset/4`  :ref:`random_protocol/0::select/3`  :ref:`random_protocol/0::select/4`  :ref:`random_protocol/0::sequence/4`  :ref:`random_protocol/0::set/4`  :ref:`pseudo_random_protocol/0::set_seed/1`  :ref:`random_protocol/0::swap/2`  :ref:`random_protocol/0::swap_consecutive/2`  

.. contents:: :local: :backlinks: top

Public predicates

.. index:: reset_seed/0 .. _fast_random/0::reset_seed/0:

reset_seed/0 ^^^^^^^^^^^^^^^^

Resets the random generator seed to its default value. Use get_seed/1 and set_seed/1 instead if you need reproducibility.

| Compilation flags: | static, synchronized

| Mode and number of proofs: | reset_seed - one

---

.. index:: randomize/1 .. _fast_random/0::randomize/1:

randomize/1 ^^^^^^^^^^^^^^^

Randomizes the random generator using a positive integer to compute a new seed. Use of a large integer is recommended. In alternative, when using a small integer argument, discard the first dozen random values.

| Compilation flags: | static, synchronized

| Template: | randomize(Seed) | Mode and number of proofs: | randomize(+positive_integer) - one

---

Protected predicates

(no local declarations; see entity ancestors if any)

Private predicates

.. index:: seed_/3 .. _fast_random/0::seed_/3:

seed_/3 ^^^^^^^^^^^

Stores the current random generator seed values.

| Compilation flags: | dynamic

| Template: | seed_(S0,S1,S2) | Mode and number of proofs: | seed_(-integer,-integer,-integer) - one

---

Operators

(none)

.. seealso::

:ref:`random <random/0>`, :ref:`backend_random <backend_random/0>`