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-rw-r--r--lib/stdlib/doc/src/rand.xml36
1 files changed, 30 insertions, 6 deletions
diff --git a/lib/stdlib/doc/src/rand.xml b/lib/stdlib/doc/src/rand.xml
index 21f680a0ee..5f1ec84786 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
@@ -254,19 +274,23 @@ tests. We suggest to use a sign test to extract a random Boolean value.</pre>
</desc>
</datatype>
<datatype>
- <name name="exs64_state"/>
+ <name name="exrop_state"/>
<desc><p>Algorithm specific internal state</p></desc>
</datatype>
<datatype>
- <name name="exsplus_state"/>
+ <name name="exs1024_state"/>
<desc><p>Algorithm specific internal state</p></desc>
</datatype>
<datatype>
- <name name="exs1024_state"/>
+ <name name="exro928_state"/>
<desc><p>Algorithm specific internal state</p></desc>
</datatype>
<datatype>
- <name name="exrop_state"/>
+ <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>