diff options
Diffstat (limited to 'lib/stdlib/doc/src')
| -rw-r--r-- | lib/stdlib/doc/src/ets.xml | 2 | ||||
| -rw-r--r-- | lib/stdlib/doc/src/rand.xml | 61 |
2 files changed, 56 insertions, 7 deletions
diff --git a/lib/stdlib/doc/src/ets.xml b/lib/stdlib/doc/src/ets.xml index f8c54fb79a..ad006f9a2b 100644 --- a/lib/stdlib/doc/src/ets.xml +++ b/lib/stdlib/doc/src/ets.xml @@ -1023,7 +1023,7 @@ ets:select(Table, MatchSpec),</code> be used in subsequent operations. The table identifier can be sent to other processes so that a table can be shared between different processes within a node.</p> - <p>Parameter <c><anno>Options</anno></c> is a list of atoms that + <p>Parameter <c><anno>Options</anno></c> is a list of options that specifies table type, access rights, key position, and whether the table is named. Default values are used for omitted options. This means that not specifying any options (<c>[]</c>) is the same diff --git a/lib/stdlib/doc/src/rand.xml b/lib/stdlib/doc/src/rand.xml index 21f680a0ee..25eec216ef 100644 --- a/lib/stdlib/doc/src/rand.xml +++ b/lib/stdlib/doc/src/rand.xml @@ -67,6 +67,26 @@ <p>Xorshift1024*, 64 bits precision and a period of 2^1024-1</p> <p>Jump function: equivalent to 2^512 calls</p> </item> + <tag><c>exro928ss</c></tag> + <item> + <p>Xoroshiro928**, 58 bits precision and a period of 2^928-1</p> + <p>Jump function: equivalent to 2^512 calls</p> + <p> + This is a 58 bit version of Xoroshiro1024**, + from the 2018 paper by David Blackman and Sebastiano Vigna: + <url href="http://vigna.di.unimi.it/ftp/papers/ScrambledLinear.pdf"> + Scrambled Linear Pseudorandom Number Generators + </url> + that on a 64 bit Erlang system executes only about 30% slower than + the default <c>exrop</c> algorithm but with much longer period + and better statistical properties, and on the flip side + a larger state. + </p> + <p> + Many thanks to Sebastiano Vigna for his help with + the 58 bit adaption. + </p> + </item> <tag><c>exsp</c></tag> <item> <p>Xorshift116+, 58 bits precision and period of 2^116-1</p> @@ -195,8 +215,8 @@ SND0 = math:sqrt(-2 * math:log(R5)) * math:cos(math:pi() * R6)</pre> </note> <p> - For all these generators the lowest bit(s) has got - a slightly less random behaviour than all other bits. + For all these generators except <c>exro928ss</c> the lowest bit(s) + has got a slightly less random behaviour than all other bits. 1 bit for <c>exrop</c> (and <c>exsp</c>), and 3 bits for <c>exs1024s</c>. See for example the explanation in the @@ -254,11 +274,32 @@ tests. We suggest to use a sign test to extract a random Boolean value.</pre> </desc> </datatype> <datatype> - <name name="exs64_state"/> - <desc><p>Algorithm specific internal state</p></desc> + <name name="seed"/> + <desc> + <p> + A seed value for the generator. + </p> + <p> + A list of integers sets the generator's internal state directly, + after algorithm-dependent checks of the value + and masking to the proper word size. + </p> + <p> + An integer is used as the initial state for a SplitMix64 generator. + The output values of that is then used for setting + the generator's internal state + after masking to the proper word size + and if needed avoiding zero values. + </p> + <p> + A traditional 3-tuple of integers seed is passed through + algorithm-dependent hashing functions to create + the generator's initial state. + </p> + </desc> </datatype> <datatype> - <name name="exsplus_state"/> + <name name="exrop_state"/> <desc><p>Algorithm specific internal state</p></desc> </datatype> <datatype> @@ -266,7 +307,15 @@ tests. We suggest to use a sign test to extract a random Boolean value.</pre> <desc><p>Algorithm specific internal state</p></desc> </datatype> <datatype> - <name name="exrop_state"/> + <name name="exro928_state"/> + <desc><p>Algorithm specific internal state</p></desc> + </datatype> + <datatype> + <name name="exsplus_state"/> + <desc><p>Algorithm specific internal state</p></desc> + </datatype> + <datatype> + <name name="exs64_state"/> <desc><p>Algorithm specific internal state</p></desc> </datatype> </datatypes> |