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SRFI 27
Source of Random Bits
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- Outdated egg!
- SRFI 27
- Documentation
- SRFI 27
- Usage
- current-random-source
- random-integer/current
- random-real/current
- registered-random-sources
- registered-random-source
- random-source?
- make-random-source
- new-random-source
- random-source-name
- random-source-documentation
- random-source-log2-period
- random-source-maximum-range
- random-source-entropy-source
- random-source-entropy-source-set!
- random-source-state-ref
- random-source-state-set!
- random-source-randomize!
- random-source-pseudo-randomize!
- random-source-make-integers
- random-source-make-reals
- random-source-make-u8vectors
- random-source-make-f64vectors
- current-entropy-source
- registered-entropy-sources
- registered-entropy-source
- entropy-source?
- make-entropy-source
- new-entropy-source
- entropy-source-name
- entropy-source-documentation
- entropy-source-u8
- entropy-source-f64
- entropy-source-u8vector
- entropy-source-f64vector
- entropy-source-integer
- Random Sources
- Entropy Sources
- Procedure Entropy Source
- Port Entropy Source
- Simple Distributions
- Vector Distributions
- Other Distributions
- Usage
- make-random-normals
- make-random-exponentials
- make-random-triangles
- make-random-poissons
- make-random-bernoullis
- make-random-binomials
- make-random-geometrics
- make-random-lognormals
- make-random-cauchys
- make-random-gammas
- make-random-erlangs
- make-random-paretos
- make-random-levys
- make-random-weibulls
- SRFI 27
- Examples
- Notes
- Bugs and Limitations
- Requirements
- Author
- Version history
- License
Documentation
A Chicken implementation of SRFI 27.
SRFI 27
Most procedures are per the SRFI 27 specification document. Only the extensions are documented here.
The most obvious extensions are support for multiple random number generators and multiple entropy sources.
Usage
(use srfi-27)
current-random-source
- current-random-source #!optional RANDOM-SOURCEprocedure
Parameter for the default random-source.
The variable default-random-source is the initial (current-random-source).
The initial random-source is an instance of 'mrg32k3a, per SRFI 27.
random-integer/current
- random-integer/currentprocedure
Returns an integer random generator from the (current-random-source).
Like random-integer but w/ (current-random-source), & a procedure, not a variable.
random-real/current
- random-real/currentprocedure
Returns a real random generator from the (current-random-source).
Like random-real but w/ (current-random-source), & a procedure, not a variable.
registered-random-sources
- registered-random-sourcesprocedure
Returns a list of the registered random-source names.
registered-random-source
- registered-random-source NAMEprocedure
Returns the random-source creator for the specified NAME or #f if not registered.
random-source?
- random-source? OBJprocedure
random-source predicate.
- check-random-source LOC OBJ #!optional NAMprocedure
Raise error when OBJ not a random-source. NAM is the optional parameter name.
- error-random-source LOC OBJ #!optional NAMprocedure
Raise error for OBJ not a random-source. NAM is the optional parameter name.
make-random-source
- make-random-source #!optional SOURCE current-random-sourceprocedure
SOURCE is either a random-source or the symbol of a registered random-source, the name.
new-random-source
- new-random-source #!optional RANDOM-SOURCE current-random-sourceprocedure
Same as (make-random-source RANDOM-SOURCE).
random-source-name
- random-source-name RANDOM-SOURCEprocedure
The symbolic name of the RANDOM-SOURCE.
random-source-documentation
- random-source-documentation RANDOM-SOURCEprocedure
Some more information for the RANDOM-SOURCE.
random-source-log2-period
- random-source-log2-period RANDOM-SOURCEprocedure
The period of the RANDOM-SOURCE as a power of 2. A fixnum.
random-source-maximum-range
- random-source-maximum-range RANDOM-SOURCEprocedure
The largest integer the RANDOM-SOURCE can produce without resort to a bignum representation. Currently an inexact-integer flonum, even for 64-bit CPUs.
random-source-entropy-source
- random-source-entropy-source RANDOM-SOURCEprocedure
The current entropy-source for the RANDOM-SOURCE.
random-source-entropy-source-set!
- random-source-entropy-source-set! RANDOM-SOURCE ENTROPY-SOURCEprocedure
Changes the current entropy-source for the RANDOM-SOURCE.
random-source-state-ref
- random-source-state-ref RANDOM-SOURCEprocedure
Per the SRFI 27 specification the random-state is a valid external representation of RANDOM-SOURCE state.
random-source-state-set!
- random-source-state-set! RANDOM-SOURCE RANDOM-STATEprocedure
Only a RANDOM-STATE produced by a random-source-state-ref of the same random-source is acceptable.
random-source-randomize!
random-source-pseudo-randomize!
random-source-make-integers
- random-source-make-integers RANDOM-SOURCEprocedure
The result is a procedure: (random-source-make-integers RANDOM-SOURCE)
random-source-make-reals
- random-source-make-reals RANDOM-SOURCE #!optional PRECISIONprocedure
The result is a procedure: (random-source-make-reals RANDOM-SOURCE PRECISION)
PRECISION maybe #f, in which case the value is flonum-epsilon.
random-source-make-u8vectors
- random-source-make-u8vectors RANDOM-SOURCEprocedure
Returns a procedure of one argument, the length of the generated vector, the returns a vector of random 8-bit unsigned values, a SRFI 4 u8vector.
The variable random-u8vector is a procedure: (random-source-make-u8vectors default-random-source)
random-source-make-f64vectors
- random-source-make-f64vectors RANDOM-SOURCE #!optional PRECISIONprocedure
Returns a procedure of one argument, the length of the generated vector, the returns a vector of random 64-bit floating-point values, a SRFI 4 f64vector.
The variable random-f64vector is a procedure: (random-source-make-f64vectors default-random-source)
current-entropy-source
- current-entropy-source #!optional ENTROPY-SOURCEprocedure
Parameter for the default entropy-source.
default-entropy-source is the initial (current-entropy-source).
The initial entropy-source is an instance of 'system-clock.
registered-entropy-sources
- registered-entropy-sourcesprocedure
Returns a list of the registered entropy-source names.
registered-entropy-source
- registered-entropy-source NAMEprocedure
Returns the entropy-source creator for the specified NAME or #f if not registered.
entropy-source?
- entropy-source? OBJprocedure
entropy-source predicate.
- check-entropy-source LOC OBJ #!optional NAMprocedure
Raise error when OBJ not an entropy-source. NAM is the optional parameter name.
- error-entropy-source LOC OBJ #!optional NAMprocedure
Raise error for OBJ not an entropy-source. NAM is the optional parameter name.
make-entropy-source
- make-entropy-source #!optional SOURCE current-entropy-sourceprocedure
SOURCE is either a entropy-source or the symbol of a registered entropy-source, the name.
new-entropy-source
- new-entropy-source ENTROPY-SOURCEprocedure
Same as (make-random-entropy ENTROPY-SOURCE).
entropy-source-name
- entropy-source-name ENTROPY-SOURCEprocedure
The symbolic name of the ENTROPY-SOURCE.
entropy-source-documentation
- entropy-source-documentation ENTROPY-SOURCEprocedure
Some more information for the ENTROPY-SOURCE.
entropy-source-u8
- entropy-source-u8 ENTROPY-SOURCEprocedure
Returns a non-negative fixnum from the ENTROPY-SOURCE.
entropy-source-f64
- entropy-source-f64 ENTROPY-SOURCEprocedure
Returns a flonum from the ENTROPY-SOURCE.
entropy-source-u8vector
- entropy-source-u8vector ENTROPY-SOURCE LENGTH #!optional U8VECTORprocedure
Returns a u8vector with the 0 thru LENGTH-1 elements filled with non-negative fixnums from the ENTROPY-SOURCE. If U8VECTOR is supplied then this is used otherwise a new vector is returned.
entropy-source-f64vector
- entropy-source-f64vector ENTROPY-SOURCE LENGTH #!optional F64VECTORprocedure
Returns a f64vector with the 0 thru LENGTH-1 elements filled with flonums from the ENTROPY-SOURCE. If F64VECTOR is supplied then this is used otherwise a new vector is returned.
entropy-source-integer
- entropy-source-integer ENTROPY-SOURCEprocedure
Returns an integer from the ENTROPY-SOURCE.
Random Sources
A random source module must be loaded before it can be used. This maybe obvious but a call of (make-random-source 'moa) will fail unless the extension "moa" is loaded.
See make-random-source for use of the NAME.
Pierre L'Ecuyer's Multiple Recursive Generator 32k3a random number generator
Usage
(use mrg32k3a)
make-random-source-mrg32k3a
- make-random-source-mrg32k3aprocedure
Registered NAME is 'mrg32k3a
George Marsaglia's Multiply With Carry random number generator
Usage
(use mwc)
make-random-source-mwc
- make-random-source-mwcprocedure
Registered NAME is 'mwc
George Marsaglia's Mother Of All random number generator
Usage
(use moa)
make-random-source-moa
- make-random-source-moaprocedure
Registered NAME is 'moa
Entropy Sources
An entropy source module must be loaded before it can be used.
System Clock
Usage
(use entropy-clock)
make-entropy-source-system-clock
- make-entropy-source-system-clockprocedure
Registered NAME is 'system-clock
Windows Crypt Device
Usage
(use entropy-windows)
make-entropy-source-crypt
- make-entropy-source-crypt #!optional BUFFER-LENGTHprocedure
Registered NAME is 'crypt
Unix Random Device
Usage
(use entropy-unix)
make-entropy-source-urandom-device
- make-entropy-source-urandom-deviceprocedure
Registered NAME is 'random-device
make-entropy-source-random-device
- make-entropy-source-random-deviceprocedure
Registered NAME is 'urandom-device
Procedure Entropy Source
U8PROC is a procedure of no arguments returning a fixnum in the range 0 .. 255.
F64PROC is a procedure of no arguments returning a finite flonum.
Usage
(use entropy-procedure)
make-entropy-source/procedures
- (make-entropy-source/procedures U8PROC F64PROC [name: (NAME (gensym 'procedures-))] [docu: (DOCU "Entropy from procedures")]) -> entropy-sourceprocedure
Returns an unregistered entropy-source built from the supplied U8PROC and F64PROC procedures.
make-entropy-source/f64procedure
- (make-entropy-source/f64procedure F64PROC [name: (NAME (gensym 'procedures-))] [docu: (DOCU "Entropy from procedures")]) -> entropy-sourceprocedure
Returns an unregistered entropy-source built from the supplied F64PROC procedure.
Port Entropy Source
Usage
(use entropy-port)
entropy-port-lifetime
- entropy-port-lifetime #!optional SECONDSparameter
The number of SECONDS an entropy port is kept open without any activity.
SECONDS is a positive real or a boolean: #t, to reset the default seconds, or #f, to determine the lifetime by GC finalization.
make-entropy-source/port
- (make-entropy-source/port PORT [name: (NAME (gensym 'port-))] [docu: (DOCU "Entropy from an open port")]) -> entropy-sourceprocedure
Returns an unregistered entropy-source built from the supplied PORT, which is treated as a binary stream.
The PORT is kept open and must be closed by the caller, if at all.
make-entropy-source/port-open
- (make-entropy-source/port-open OPENER [name: (NAME (gensym 'port-))] [docu: (DOCU "Entropy from port")]) -> entropy-sourceprocedure
Returns an unregistered entropy-source built from the supplied OPENER.
OPENER is a (procedure () port), returning an opened port.
The returned port has an (entropy-port-lifetime) so the port may be closed and OPENER called more than once.
make-entropy-source/port-open-timed
- (make-entropy-source/port-open-timed OPENER SECONDS [name: (NAME (gensym 'timed-port-))] [docu: (DOCU "Entropy from timed open port")]) -> entropy-sourceprocedure
Returns an unregistered entropy-source built from the supplied OPENER & SECONDS.
SECONDS is interpreted as with entropy-port-lifetime.
OPENER is interpreted as with make-entropy-source/port-open.
make-entropy-source/file
- (make-entropy-source/file NAMSTR [name: (NAME (gensym 'file-))] [docu: (DOCU (string-append "Entropy from file \"" namstr "\""))]) -> entropy-sourceprocedure
Returns an unregistered entropy-source using the file named by the pathname NAMSTR.
The opened port for the file NAMSTR is interpreted as with make-entropy-source/port-open.
Simple Distributions
Provides exact and inexact generators. All return 2 values: the generator itself and a procedure returning the argument values used to parameterize the generator. The second return value can be ignored.
Usage
(use srfi-27-uniform-random)
make-uniform-random-integers
- (make-uniform-random-integers [high: (HIGH #f)] [low: (LOW 0)] [precision: (PRECISION 1)] [source: (SOURCE (current-random-source))]) -> (procedure () integer)procedure
LOW, HIGH and PRECISION are integers.
SOURCE is a random-source.
HIGH, if not supplied, is the (- (random-source-maximum-range source) 1).
The generator returns integers in the range LOW .. HIGH with an index of PRECISION. Unlike a (random-integer) result negative integers are possible.
(random-integer/current) <> (make-uniform-random-integers). (random-integer/current) returns ((integer) -> integer). (make-uniform-random-integers) returns (() -> integer).
make-uniform-random-reals
- (make-uniform-random-reals [precision: PRECISION] [source: (SOURCE (current-random-source))]) -> (procedure () real)procedure
The generator is as (random-source-make-reals SOURCE PRECISION).
PRECISION maybe #f, in which case the value is flonum-epsilon.
SOURCE is a random-source.
(random-real/current) = (make-uniform-random-reals). Both return procedures of (() -> real).
Vector Distributions
The procedures named as per make-random-... return a procedure of one argument N, the length of the vector to be created.
The nomenclature vector% is used to indicate a disjoint type union of vector, f32vector, f64vector. If the user is really keen to access the API for this type it is available in the, undocumented, "srfi-27-vector-support" module.
Usage
(use srfi-27-vector)
make-random-permutations
random-permutation!
- (make-random-permutations [randoms: (RANDOMS random-integer/current)]) -> (procedure (integer) vector)procedure
- (random-permutation! VECTOR [randoms: (RANDOMS random-integer/current)]) -> vectorprocedure
Performs the "Knuth shuffle" (or "Fisher-Yates shuffle").
Fills VECTOR with a random permutation of the finite set {0 ... N-1}, where N = (vector-length VECTOR).
RANDOMS is a procedure: (exact-real) -> exact-real
(From Gambit)
make-random-vector
random-vector!
- (make-random-vector [randoms: (RANDOMS random-real/current)]) -> (procedure (integer) vector)procedure
- (random-vector! VECTOR% [randoms: (RANDOMS random-real/current)]) -> vector%procedure
Fills VECTOR with inexact real random numbers from the random distribution generator randoms.
RANDOMS is a procedure: () -> inexact-real
make-random-hollow-sphere
random-hollow-sphere!
- (make-random-hollow-sphere [mu: (MU 0.0)] [sigma: (SIGMA 1.0)] [randoms: (RANDOMS (random-real/current))]) -> (procedure (integer) vector)procedure
- (random-hollow-sphere! VECTOR% [mu: (MU 0.0)] [sigma: (SIGMA 1.0)] [randoms: (RANDOMS (random-real/current))]) -> vector%procedure
Fills VECTOR% with inexact real random numbers the sum of whose squares are equal to 1.0.
Thinking of VECTOR% as coordinates in space of dimension N = (vector%-length VECTOR%), the coordinates are uniformly distributed over the surface of the unit n-sphere.
(From Gambit)
make-random-solid-sphere
random-solid-sphere!
- (make-random-solid-sphere [mu: (MU 0.0)] [sigma: (SIGMA 1.0)] [randoms: (RANDOMS (random-real/current))]) -> (procedure (integer) vector)procedure
- (random-solid-sphere! VECTOR% [mu: (MU 0.0)] [sigma: (SIGMA 1.0)] [randoms: (RANDOMS (random-real/current))]) -> vector%procedure
Fills VECTOR% with inexact real random numbers the sum of whose squares are less than 1.0.
Thinking of VECTOR% as coordinates in space of dimension N = (vector%-length VECTOR%), the coordinates are uniformly distributed within the unit n-sphere.
(From Gambit)
Other Distributions
Provides generators for some common distributions ranging over some subset of the inexact-reals. The domain of the generators depends, of course, on the specific distribution.
All return 2 values: the generator itself and a procedure returning the argument values used to parameterize the generator. The second return value can be ignored.
The identifiers matching *make-random-<distribution> are reserved.
Usage
(use srfi-27-distributions)
All distributions are available from the omnibus module srfi-27-distributions, and individually as the srfi-27-<distribution> module.
make-random-normals
- (make-random-normals [mu: (MU 0.0)] [sigma: (SIGMA 1.0)] [randoms: (RANDOMS (random-real/current))]) -> (procedure () real)procedure
MU is real.
SIGMA is nonzero-real.
RANDOMS is a (procedure () real)
(use srfi-27-normals)
make-random-exponentials
- (make-random-exponentials [mu: (MU 1.0)] [randoms: (RANDOMS (random-real/current))]) -> (procedure () real)procedure
MU is real in [0 1].
RANDOMS is a (procedure () real)
(use srfi-27-exponentials)
make-random-triangles
- (make-random-triangles [s: (S 0.0)] [m: (M 0.5)] [l: (L 1.0)] [randoms: (RANDOMS (random-real/current))]) -> (procedure () real)procedure
S is real.
M is real in [S L].
L is real in ]S +inf.0[.
RANDOMS is a (procedure () real)
(use srfi-27-triangles)
make-random-poissons
- (make-random-poissons [mu: (MU 1.0)] [randoms: (RANDOMS (random-real/current))]) -> (procedure () integer)procedure
MU is nonnegative-real.
RANDOMS is a (procedure () real)
(use srfi-27-poissons)
make-random-bernoullis
- (make-random-bernoullis [p: (P 0.5)] [randoms: (RANDOMS (random-real/current))]) -> (procedure () boolean)procedure
P is real in [0 1].
RANDOMS is a (procedure () real)
(use srfi-27-bernoullis)
make-random-binomials
- (make-random-binomials [t: (T 1)] [p: (P 0.5)] [randoms: (RANDOMS (random-real/current))]) -> (procedure () integer)procedure
T is cardinal-integer.
P is real in [0 1].
RANDOMS is a (procedure () real)
(use srfi-27-binomials)
make-random-geometrics
- (make-random-geometrics [p: (P 0.5)] [randoms: (RANDOMS (random-real/current))])) -> (procedure () integer)procedure
P is real in [0 1].
RANDOMS is a (procedure () real)
(use srfi-27-geometrics)
make-random-lognormals
- (make-random-lognormals [mu: (MU 1.0)] [sigma: (SIGMA 1.0)] [randoms: (RANDOMS (random-real/current))]) -> (procedure () real)procedure
MU is nonzero-real.
SIGMA is nonnegative-real.
RANDOMS is a (procedure () real)
(use srfi-27-lognormals)
make-random-cauchys
- (make-random-cauchys [median: (MEDIAN 0.0)] [sigma: (SIGMA 1.0)] [randoms: (RANDOMS (random-real/current))]) -> (procedure () real)procedure
MEDIAN is real.
SIGMA is positive-real.
RANDOMS is a (procedure () real)
(use srfi-27-cauchys)
make-random-gammas
- (make-random-gammas [alpha: (ALPHA 1.0)] [theta: (THETA 1.0)] [randoms: (RANDOMS (random-real/current))]) -> (procedure () real)procedure
ALPHA is positive-real.
THETA is positive-real.
RANDOMS is a (procedure () real)
(use srfi-27-gammas)
make-random-erlangs
- (make-random-erlangs [alpha: (ALPHA 1)] [theta: (THETA 1.0)] [randoms: (RANDOMS (random-real/current))]) -> (procedure () real)procedure
ALPHA is positive-real.
THETA is positive-real.
RANDOMS is a (procedure () real)
(use srfi-27-erlangs)
make-random-paretos
- (make-random-paretos [alpha: (ALPHA 1.0)] [xmin: (XMIN 1.0)] [randoms: (RANDOMS (random-real/current))]) -> (procedure () real)procedure
ALPHA is positive-real.
XMIN is positive-real.
RANDOMS is a (procedure () real)
(use srfi-27-paretos)
make-random-levys
- (make-random-levys [gamma: (GAMMA 1.0)] [delta: (DELTA 0.0)] [randoms: (RANDOMS (random-real/current))]) -> (procedure () real)procedure
GAMMA is nonnegative-real.
DELTA is positive-real.
RANDOMS is a (procedure () real)
(use srfi-27-levys)
make-random-weibulls
- (make-random-weibulls [shape: (SHAPE 1.0)] [scale: (SCALE 1.0)] [randoms: (RANDOMS (random-real/current))]) -> (procedure () real)procedure
SHAPE is positive-real.
SCALE is positive-real.
RANDOMS is a (procedure () real)
(use srfi-27-weibulls)
Examples
- A procedure for creating K-vector (whatever that is) generators. The use of George Marsaglia's Multiply With Carry random-source and the "/dev/random" entropy-source are for exposition only.
(use entropy-unix entropy-port mwc srfi-27 srfi-27-uniform-random srfi-27-vector) (define (make-random-k-vector #!optional (k 1024) (rs (make-random-source 'mwc)) es) (let ( (new-es (or es ;don't keep open port around too much (parameterize ((entropy-port-lifetime 30)) (make-entropy-source-random-device)))) (old-es (random-source-entropy-source rs)) ) (dynamic-wind (lambda () (random-source-entropy-source-set! rs new-es) ) (lambda () (let* ( (rnd (make-uniform-random-integers low: (- k) high: (+ k) precision: 2 source: rs)) (vecgen (make-random-vector randoms: rnd)) ) (lambda (#!optional (k k)) (vecgen k)) ) ) (lambda () (random-source-entropy-source-set! rs old-es) ) ) ) )
- Providing a fixed entropy-source, a constant seed.
(use data-structures entropy-procedure) (define (make-entropy-constant n) (make-entropy-source/f64procedure (constantly (exact->inexact n)) name: (string->uninterned-symbol (conc "entropy-constant-" n)) docu: (conc "Entropy constant " n)) )
- A silly OO version of a random distribution generator
(use srfi-1 srfi-13) (use coops) (use srfi-27-normals srfi-27-exponentials) ;; Named (has a name) "concept" (define-generic (name obj)) (define-class <named> () ( (namsym reader: name) ) ) ;; Parameterized extension "concept" (define-class <parameterized> () (ctor params src)) ;; Moves forward thru a set of values "concept" (define-generic (next-value obj)) (define-class <stepper> () (nxtval)) (define-method (next-value (obj <stepper>)) ((slot-value obj 'nxtval))) (define-generic (reset obj)) (define-method (reset (obj <stepper>)) (let-values ( ((gen _) (apply (slot-value obj 'ctor) `(,@(slot-value obj 'params) ,(slot-value obj 'src)))) ) (set! (slot-value obj 'nxtval) gen) ) ) ;; Parameterized generative set of random values "concept" (define-class <random-distribution> (<named> <parameterized> <stepper>) ( ;holds any value, temporarily tmpval ) ) ;; Create an instance of <random-distribution> where the arguments are ;; the same as the documented procedural distribution API. ;; ;; SRFI 27 API: ({some distribution constructor} arg...) ;; OO API: (make-random-distribution {some distribution constructor} arg...) (define-syntax make-random-distribution (syntax-rules () ((_ ?ctor ?arg0 ...) ;use tmpval to hold the ctor call form (make <random-distribution> 'tmpval (list ?ctor ?arg0 ...)) ) ) ) (define-method (initialize-instance (obj <random-distribution>)) ; The 'ctor' must be a globally defined procedure compiled with ; procedure-information. So if following nomenclature then the last ; procedure name element will be the kind of distribution: ; make-random-<distribution>. And the <random-source> will be the ; last argument. ; ; (I do not endorse this kind of "auto-magic". For example only.) (let* ( (tmpval (or (slot-value obj 'tmpval) `(,make-random-normals))) (ctor (car tmpval) ) (procinfo (procedure-information ctor)) (procname (and procinfo (pair? procinfo) (symbol->string (car procinfo)))) (procname (and procname (and-let* ((kndpos (string-index-right procname #\-))) (substring/shared procname (add1 kndpos))))) (procname (or procname "impossible")) (dstr-vals (receive (apply ctor (cdr tmpval)))) (params (and (<= 2 (length dstr-vals)) (receive ((second dstr-vals))))) ) ;"free" the temp slot (set! (slot-value obj 'tmpval) #f) ;initialize state (set! (slot-value obj 'namsym) (string->symbol procname)) (set! (slot-value obj 'nxtval) (first dstr-vals)) (set! (slot-value obj 'ctor) ctor) (set! (slot-value obj 'params) (and params (drop-right params 1))) (set! (slot-value obj 'src) (and params (last params))) ) ) ;; Use it (use coops-extras) (define expn-rd (make-random-distribution make-random-exponentials mu: 0.5)) (describe-object expn-rd) ;coops instance of class `<random-distribution>': ;tmpval: #f ;namsym: exponentials ; ctor: #<procedure (srfi-27-exponentials#make-random-exponentials . tmp302303)> ;params: (0.5) ; src: #<procedure> ;nxtval: #<procedure (f_1191)> (next-value expn-rd) ;=> ...
Notes
- Due to the SRFI 27 requirement to generate numbers of any precision the "numbers" extension is always loaded. Be careful of creating a generator in a calling context where extended range is possible and consuming the results of the generator in a context without such range.
- Portions by Sebastian Egner and Brad Lucier. (See the "book" SRFI 27 implementation.)
Bugs and Limitations
- Support for 64-bit platforms is poor. Need to provide core random integer generators which are defined over the 64-bit integer range. Currently 64-bit fixnum bounds are processed as if using a 32-bit platform. However, due to the bignum implementation, results in the 64-bit fixnum range are coerced to fixnum.
- The random distribution API is poorly documented.
- The implementation API is not documented. See the source distribution.
- Use of an entropy-source as a random-source is impossible without the undocumented implementation API.
Requirements
miscmacros numbers check-errors vector-lib timed-resource mathh
Author
Version history
- 3.4.1
- Fix for composite-entropy-source.
- 3.4.0
- Added types.
- 3.3.2
- Added types (except entropy & vector modules). entropy-source-random & entropy-source-urandom are timed-resources.
- 3.3.1
- Remove unfinished entropy-linux module per #1434.
- 3.3.0
- Added 14 distribution modules.
- 3.2.11
- Include composite-random-source & composite-entropy-source, since tested.
- 3.2.10
- Uses test egg now.
- 3.2.9
- Fix make-random-bernoullis, add distributions test.
- 3.2.8
- .
- 3.2.7
- Fix entropy-source-system-clock entropy-source-u8.
- 3.2.6
- Add random-integer/current, random-real/current. Doesn't use synch, thread-utils eggs. Fix make-uniform-random-integers.
- 3.2.5
- Revert to own clock entropy implementation. Fix vector map/fill. Use EXTERNAL-ID for name.
- 3.2.4
- Error when unregistered source.
- 3.2.3
- Rename registration -> source-registration. Fix random-source-entropy-source-set!, must accept #f entropy-source. Fix broken srfi-27-vector.
- 3.2.2
- more tests.
- 3.2.1
- fp-extn module.
- 3.2.0
- Include registration.scm.
- 3.1.9
- registration module.
- 3.1.8
- Fix for ticket #630.
- 3.1.7
- Fix for unsigned integer from entropic f64.
- 3.1.6
- Fix for composite-random-source missing argument.
- 3.1.5
- Fix for mrg32k3a bad state values.
- 3.1.4
- Fix for mrg32k3a-pack-state bad index.
- 3.1.3
- Fix for 64-bit fixnums and random integers.
- 3.1.2
- Fix for "entropy-windows" make-entropy-source-crypt.
- 3.1.1
- Moved thread stuff to own extensions.
- 3.1.0
- Changed all random-source-name to lowercase symbols. Changed random-state tags to same as random-source-name. Added new-(random|entropy)-source, @(random|entropy)-source-constructor & (random|entropy)-source-name. Exported registered-(random|entropy)-sources & registered-(random|entropy)-source.
- 3.0.1
- Bug fix for bad external state symbol. Use of 64-bit arithmetic instead of double in C code.
- 3.0.0
- Initial release for Chicken 4
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