HELP: seed-random
{ $values
- { "tuple" "a random number generator" }
+ { "obj" "a random number generator" }
{ "seed" "a seed specific to the random number generator" }
- { "tuple'" "a random number generator" }
}
{ $description "Seed the random number generator. Repeatedly seeding the random number generator should provide the same sequence of random numbers." }
{ $notes "Not supported on all random number generators." } ;
HELP: random-32*
-{ $values { "tuple" "a random number generator" } { "r" "an integer between 0 and 2^32-1" } }
+{ $values { "obj" "a random number generator" } { "r" "an integer between 0 and 2^32-1" } }
{ $description "Generates a random 32-bit unsigned integer." } ;
HELP: random-bytes*
-{ $values { "n" "an integer" } { "tuple" "a random number generator" } { "byte-array" "a sequence of random bytes" } }
+{ $values { "n" "an integer" } { "obj" "a random number generator" } { "byte-array" "a sequence of random bytes" } }
{ $description "Generates a byte-array of random bytes." } ;
HELP: random
{ $description "Outputs an random integer n bits in length." } ;
HELP: random-bits*
-{ $values
- { "numbits" integer }
- { "n" integer }
-}
+{ $values { "numbits" integer } { "r" "a random integer" } }
{ $description "Returns an integer exactly " { $snippet "numbits" } " in length, with the topmost bit set to one." } ;
HELP: with-random
-{ $values { "tuple" "a random generator" } { "quot" "a quotation" } }
-{ $description "Calls the quotation with the random generator in a dynamic variable. All random numbers will be generated using this random generator." } ;
+{ $values { "obj" "a random number generator" } { "quot" "a quotation" } }
+{ $description "Calls the quotation with the random number generator in a dynamic variable. All random numbers will be generated using this random number generator." } ;
HELP: with-secure-random
{ $values { "quot" "a quotation" } }
-{ $description "Calls the quotation with the secure random generator in a dynamic variable. All random numbers will be generated using this random generator." } ;
+{ $description "Calls the quotation with the secure random number generator in a dynamic variable. All random numbers will be generated using this random number generator." } ;
HELP: with-system-random
{ $values { "quot" "a quotation" } }
-{ $description "Calls the quotation with the system's random generator in a dynamic variable. All random numbers will be generated using this random generator." } ;
+{ $description "Calls the quotation with the system's random number generator in a dynamic variable. All random numbers will be generated using this random number generator." } ;
{ with-random with-secure-random with-system-random } related-words
SYMBOL: secure-random-generator
SYMBOL: random-generator
-GENERIC# seed-random 1 ( tuple seed -- tuple' )
-GENERIC: random-32* ( tuple -- r )
-GENERIC: random-bytes* ( n tuple -- byte-array )
+GENERIC# seed-random 1 ( obj seed -- obj )
+GENERIC: random-32* ( obj -- r )
+GENERIC: random-bytes* ( n obj -- byte-array )
-M: object random-bytes* ( n tuple -- byte-array )
+M: object random-bytes* ( n obj -- byte-array )
[ integer>fixnum-strict [ <byte-array> ] keep ] dip
[ over 4 >= ] [
[ 4 - ] dip
random-32* c:int <ref> swap head 0 pick copy-unsafe
] if ;
-M: object random-32* ( tuple -- r )
+M: object random-32* ( obj -- r )
4 swap random-bytes* c:uint deref ;
ERROR: no-random-number-generator ;
<PRIVATE
-: #bits ( n -- bits )
+:: (random-bits) ( numbits obj -- r )
+ numbits 32 > [
+ obj random-32* numbits 32 - [ dup 32 > ] [
+ [ 32 shift obj random-32* + ] [ 32 - ] bi*
+ ] while [
+ [ shift ] keep obj random-32* swap bits +
+ ] unless-zero
+ ] [
+ obj random-32* numbits bits
+ ] if ; inline
+
+PRIVATE>
+
+: random-bits ( numbits -- r )
+ random-generator get (random-bits) ;
+
+: random-bits* ( numbits -- r )
+ 1 - [ random-bits ] keep set-bit ;
+
+<PRIVATE
+
+: next-power-of-2-bits ( n -- numbits )
dup 2 <= [ drop 1 ] [ 1 - log2 1 + ] if ; inline
-:: (random-bits) ( n bits obj -- n' )
- obj random-32* 32 bits 32 - [ dup 0 > ] [
+:: ((random-integer)) ( n obj -- r )
+ obj random-32* 32 n next-power-of-2-bits 32 - [ dup 0 > ] [
[ 32 shift obj random-32* + ] [ 32 + ] [ 32 - ] tri*
] while drop [ n * ] [ neg shift ] bi* ; inline
-: ((random-integer)) ( n obj -- n' )
- [ dup #bits ] dip (random-bits) ; inline
-
-GENERIC# (random-integer) 1 ( n obj -- n )
-M: fixnum (random-integer) ( n obj -- n' ) ((random-integer)) ;
-M: bignum (random-integer) ( n obj -- n' ) ((random-integer)) ;
+GENERIC# (random-integer) 1 ( n obj -- r )
+M: fixnum (random-integer) ( n obj -- r ) ((random-integer)) ;
+M: bignum (random-integer) ( n obj -- r ) ((random-integer)) ;
-: random-integer ( n -- n' )
+: random-integer ( n -- r )
random-generator get (random-integer) ;
PRIVATE>
-: random-bits ( numbits -- r )
- [ 2^ ] keep random-generator get (random-bits) ;
-
-: random-bits* ( numbits -- n )
- 1 - [ random-bits ] keep set-bit ;
-
GENERIC: random ( obj -- elt )
-M: integer random [ f ] [ random-integer ] if-zero ;
+M: integer random
+ [ f ] [ random-integer ] if-zero ;
M: sequence random
[ f ] [
[ length random-integer ] keep
[ nth ] 2keep remove-nth! drop ;
-: with-random ( tuple quot -- )
+: with-random ( obj quot -- )
random-generator swap with-variable ; inline
: with-system-random ( quot -- )
: random-integers ( length n -- sequence )
random-generator get '[ _ _ (random-integer) ] replicate ;
+<PRIVATE
+
: (cos-random-float) ( -- n )
0. 2pi uniform-random-float cos ;
: (log-sqrt-random-float) ( -- n )
random-unit log -2. * sqrt ;
+PRIVATE>
+
: normal-random-float ( mean sigma -- n )
(cos-random-float) (log-sqrt-random-float) * * + ;
: pareto-random-float ( k alpha -- n )
[ random-unit ] dip recip ^ /f ;
+<PRIVATE
+
:: (gamma-random-float>1) ( alpha beta -- n )
! Uses R.C.H. Cheng, "The generation of Gamma
! variables with non-integral shape parameters",
] if x!
] do while x beta * ;
+PRIVATE>
+
: gamma-random-float ( alpha beta -- n )
{
{ [ over 1 > ] [ (gamma-random-float>1) ] }
rnd (random-unit) 0.5 > [ + ] [ - ] if
] if ;
+<PRIVATE
+
:: (triangular-random-float) ( low high mode -- n )
mode low - high low - / :> c!
random-unit :> u!
u c > [ 1. u - u! 1. c - c! swap ] when
[ - u c * sqrt * ] keep + ;
+PRIVATE>
+
: triangular-random-float ( low high -- n )
2dup + 2 /f (triangular-random-float) ;