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Pack logtalk -- logtalk-3.86.0/docs/_sources/random_protocol_0.rst.txt

.. index:: random_protocol .. _random_protocol/0:

.. rst-class:: right

protocol

random_protocol

Random number generator protocol. The predicates are declared as synchronized when the library is compiled using a backend supporting threads.

| Availability: | logtalk_load(random(loader))

| Author: Paulo Moura | Version: 3:3:0 | Date: 2023-11-24

| Compilation flags: | static

| Dependencies: | (none)

| Remarks: | (none)

| Inherited public predicates: | (none)

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

Public predicates

.. index:: random/1 .. _random_protocol/0::random/1:

random/1 ^^^^^^^^^^^^

Returns a new random float value in the interval [0.0, 1.0[.

| Compilation flags: | static, synchronized

| Template: | random(Random) | Mode and number of proofs: | random(-float) - one


.. index:: between/3 .. _random_protocol/0::between/3:

between/3 ^^^^^^^^^^^^^

Returns a new random integer in the interval [Lower, Upper]. Fails if Lower or Upper are not integers or if Lower > Upper.

| Compilation flags: | static

| Template: | between(Lower,Upper,Random) | Mode and number of proofs: | between(+integer,+integer,-integer) - zero_or_one


.. index:: member/2 .. _random_protocol/0::member/2:

member/2 ^^^^^^^^^^^^

Returns a random member of a list. Fails if the list is empty.

| Compilation flags: | static

| Template: | member(Random,List) | Mode and number of proofs: | member(-term,+list(term)) - zero_or_one


.. index:: select/3 .. _random_protocol/0::select/3:

select/3 ^^^^^^^^^^^^

Returns a random member of a list and the rest of the list. Fails if the list is empty.

| Compilation flags: | static

| Template: | select(Random,List,Rest) | Mode and number of proofs: | select(-term,+list(term),-list(term)) - zero_or_one


.. index:: select/4 .. _random_protocol/0::select/4:

select/4 ^^^^^^^^^^^^

Returns a random member of a list, replacing it with a new element and returning the resulting list.

| Compilation flags: | static

| Template: | select(Random,OldList,New,NewList) | Mode and number of proofs: | select(-term,+list(term),@term,-list(term)) - zero_or_one


.. index:: swap/2 .. _random_protocol/0::swap/2:

swap/2 ^^^^^^^^^^

Swaps two randomly selected elements of a list. Fails if the list is empty or contains a single element.

| Compilation flags: | static

| Template: | swap(OldList,NewList) | Mode and number of proofs: | swap(-term,+list(term)) - zero_or_one


.. index:: swap_consecutive/2 .. _random_protocol/0::swap_consecutive/2:

swap_consecutive/2 ^^^^^^^^^^^^^^^^^^^^^^

Swaps two randomly selected consecutive elements of a list. Fails if the list is empty or contains a single element.

| Compilation flags: | static

| Template: | swap_consecutive(OldList,NewList) | Mode and number of proofs: | swap_consecutive(-term,+list(term)) - zero_or_one


.. index:: enumerate/2 .. _random_protocol/0::enumerate/2:

enumerate/2 ^^^^^^^^^^^^^^^

Enumerates the elements of a list in random order. Fails if the list is empty.

| Compilation flags: | static

| Template: | enumerate(List,Random) | Mode and number of proofs: | enumerate(+list(term),--term) - zero_or_more


.. index:: permutation/2 .. _random_protocol/0::permutation/2:

permutation/2 ^^^^^^^^^^^^^^^^^

Returns a random permutation of a list.

| Compilation flags: | static, synchronized

| Template: | permutation(List,Permutation) | Mode and number of proofs: | permutation(+list,-list) - one


.. index:: sequence/4 .. _random_protocol/0::sequence/4:

sequence/4 ^^^^^^^^^^^^^^

Returns list of random integers of given length in random order in interval [Lower, Upper]. Fails if Length, Lower, or Upper are not integers or if Lower > Upper.

| Compilation flags: | static, synchronized

| Template: | sequence(Length,Lower,Upper,List) | Mode and number of proofs: | sequence(+integer,+integer,+integer,-list(integer)) - zero_or_one


.. index:: set/4 .. _random_protocol/0::set/4:

set/4 ^^^^^^^^^

Returns ordered set of random integers of given size in interval [Lower, Upper]. Fails if Length, Lower, or Upper are not integers, if Lower > Upper, or if Length > Upper - Lower + 1.

| Compilation flags: | static, synchronized

| Template: | set(Length,Lower,Upper,Set) | Mode and number of proofs: | set(+integer,+integer,+integer,-list(integer)) - zero_or_one


.. index:: random/3 .. _random_protocol/0::random/3:

random/3 ^^^^^^^^^^^^

Returns a new random value in the interval [Lower, Upper[. Fails if Lower > Upper. Deprecated. Use between/3 for integers.

| Compilation flags: | static, synchronized

| Template: | random(Lower,Upper,Random) | Mode and number of proofs: | random(+integer,+integer,-integer) - zero_or_one | random(+float,+float,-float) - zero_or_one


.. index:: randseq/4 .. _random_protocol/0::randseq/4:

randseq/4 ^^^^^^^^^^^^^

Returns list of random values of given length in random order in interval [Lower, Upper[. Fails if Lower > Upper or if the arguments are neither integers or floats. Deprecated. Use sequence/4 for integers.

| Compilation flags: | static, synchronized

| Template: | randseq(Length,Lower,Upper,List) | Mode and number of proofs: | randseq(+integer,+integer,+integer,-list(integer)) - zero_or_one | randseq(+integer,+float,+float,-list(float)) - zero_or_one


.. index:: randset/4 .. _random_protocol/0::randset/4:

randset/4 ^^^^^^^^^^^^^

Returns ordered set of random values of given size in interval [Lower, Upper[. Fails if the arguments are neither integers or floats, Lower > Upper, or Length > Upper - Lower when arguments are integers. Deprecated. Use set/4 for integers.

| Compilation flags: | static, synchronized

| Template: | randset(Length,Lower,Upper,Set) | Mode and number of proofs: | randset(+integer,+integer,+integer,-list(integer)) - zero_or_one | randset(+integer,+float,+float,-list(float)) - zero_or_one


.. index:: maybe/0 .. _random_protocol/0::maybe/0:

maybe/0 ^^^^^^^^^^^

Succeeds or fails with equal probability.

| Compilation flags: | static

| Mode and number of proofs: | maybe - zero_or_one


.. index:: maybe/1 .. _random_protocol/0::maybe/1:

maybe/1 ^^^^^^^^^^^

Succeeds with probability Probability or fails with probability 1 - Probability. Fails if Probability is not a float or is outside the interval [0.0, 1.0].

| Compilation flags: | static

| Template: | maybe(Probability) | Mode and number of proofs: | maybe(+probability) - zero_or_one


.. index:: maybe/2 .. _random_protocol/0::maybe/2:

maybe/2 ^^^^^^^^^^^

Succeeds with probability K/N where K and N are integers satisfying the equation 0 =< K =< N. Fails otherwise.

| Compilation flags: | static

| Template: | maybe(K,N) | Mode and number of proofs: | maybe(+non_negative_integer,+non_negative_integer) - zero_or_one


.. index:: maybe_call/1 .. _random_protocol/0::maybe_call/1:

maybe_call/1 ^^^^^^^^^^^^^^^^

Calls a goal or fails without calling it with equal probability. When the goal is called, it determines if this predicate succeeds once or fails.

| Compilation flags: | static

| Template: | maybe_call(Goal) | Meta-predicate template: | maybe_call(0) | Mode and number of proofs: | maybe_call(+callable) - zero_or_one


.. index:: maybe_call/2 .. _random_protocol/0::maybe_call/2:

maybe_call/2 ^^^^^^^^^^^^^^^^

Calls a goal or fails without calling it with probability Probability. When the goal is called, it determines if this predicate succeeds once or fails.

| Compilation flags: | static

| Template: | maybe_call(Probability,Goal) | Meta-predicate template: | maybe_call(*,0) | Mode and number of proofs: | maybe_call(+probability,+callable) - zero_or_one


Protected predicates

(none)

Private predicates

(none)

Operators

(none)

.. seealso::

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