570 lines
20 KiB
Scheme
570 lines
20 KiB
Scheme
; MODULE DEFINITION FOR SRFI-27, C/SCHEME-IMPLEMENTATION
|
|
; ======================================================
|
|
;
|
|
; Sebastian.Egner@philips.com, Mar-2002, in Scheme 48 0.57
|
|
;
|
|
; This file contains the top-level definition for the C-code
|
|
; implementation of SRFI-27 for the Scheme 48 0.57 system.
|
|
;
|
|
; 1. The core generator is implemented in 'mrg32k3a-b.c'.
|
|
; 2. The generic parts of the interface are in 'mrg32k3a.scm'.
|
|
; 3. The non-generic parts (record type, time, error, C-bindings) are here.
|
|
;
|
|
; creating the module:
|
|
; copy mrg32k3a-b.c into $SCHEME48/c/srfi-27/mrg32k3a-b.c
|
|
; edit $SCHEME48/Makefile.in
|
|
; add c/srfi-27/mrg32k3a-b.o to EXTERNAL_OBJECTS
|
|
; add mrg32k3a_init to EXTERNAL_INITIALIZERS
|
|
; add the make line c/srfi-27/mrg32k3a-b.o: c/scheme48.h
|
|
; cd $SCHEME48
|
|
; make clean
|
|
; configure
|
|
; make
|
|
; cd $SRFI27
|
|
; ,config ,load srfi-27-b.scm
|
|
;
|
|
; loading the module, once created:
|
|
; ,open srfi-27
|
|
;
|
|
; history of this file:
|
|
; SE, 22-Mar-2002: initial version
|
|
; SE, 25-Mar-2002: initial version
|
|
; MG, September 2002: merged in mrg32k2a.scm, move package definitons to
|
|
; more-packages.scm
|
|
|
|
(define-record-type :random-source
|
|
(:random-source-make
|
|
state-ref
|
|
state-set!
|
|
randomize!
|
|
pseudo-randomize!
|
|
make-integers
|
|
make-reals)
|
|
:random-source?
|
|
(state-ref :random-source-state-ref)
|
|
(state-set! :random-source-state-set!)
|
|
(randomize! :random-source-randomize!)
|
|
(pseudo-randomize! :random-source-pseudo-randomize!)
|
|
(make-integers :random-source-make-integers)
|
|
(make-reals :random-source-make-reals))
|
|
|
|
; We have neither scsh nor posix...
|
|
; (define (:random-source-current-time)
|
|
; (time-seconds (current-time)))
|
|
(import-lambda-definition :random-source-current-time () "current_time")
|
|
|
|
; interface to core generator
|
|
|
|
(import-lambda-definition mrg32k3a-pack-state1 (state))
|
|
(import-lambda-definition mrg32k3a-unpack-state1 (state))
|
|
(import-lambda-definition mrg32k3a-random-range ())
|
|
(import-lambda-definition mrg32k3a-random-integer (state range))
|
|
(import-lambda-definition mrg32k3a-random-real (state))
|
|
|
|
(define (mrg32k3a-pack-state state)
|
|
(mrg32k3a-pack-state1
|
|
(list->vector
|
|
(apply append
|
|
(map (lambda (x)
|
|
(list (modulo x 65536)
|
|
(quotient x 65536)))
|
|
(vector->list state))))))
|
|
|
|
(define (mrg32k3a-unpack-state state)
|
|
(let ((s (mrg32k3a-unpack-state1 state)) (w 65536))
|
|
(vector
|
|
(+ (vector-ref s 0) (* (vector-ref s 1) w))
|
|
(+ (vector-ref s 2) (* (vector-ref s 3) w))
|
|
(+ (vector-ref s 4) (* (vector-ref s 5) w))
|
|
(+ (vector-ref s 6) (* (vector-ref s 7) w))
|
|
(+ (vector-ref s 8) (* (vector-ref s 9) w))
|
|
(+ (vector-ref s 10) (* (vector-ref s 11) w)))))
|
|
; GENERIC PART OF MRG32k3a-GENERATOR FOR SRFI-27
|
|
; ==============================================
|
|
;
|
|
; Sebastian.Egner@philips.com, 2002.
|
|
;
|
|
; This is the generic R5RS-part of the implementation of the MRG32k3a
|
|
; generator to be used in SRFI-27. It is based on a separate implementation
|
|
; of the core generator (presumably in native code) and on code to
|
|
; provide essential functionality not available in R5RS (see below).
|
|
;
|
|
; compliance:
|
|
; Scheme R5RS with integer covering at least {-2^53..2^53-1}.
|
|
; In addition,
|
|
; SRFI-23: error
|
|
;
|
|
; history of this file:
|
|
; SE, 22-Mar-2002: refactored from earlier versions
|
|
; SE, 25-Mar-2002: pack/unpack need not allocate
|
|
; SE, 27-Mar-2002: changed interface to core generator
|
|
; SE, 10-Apr-2002: updated spec of mrg32k3a-random-integer
|
|
|
|
; Generator
|
|
; =========
|
|
;
|
|
; Pierre L'Ecuyer's MRG32k3a generator is a Combined Multiple Recursive
|
|
; Generator. It produces the sequence {(x[1,n] - x[2,n]) mod m1 : n}
|
|
; defined by the two recursive generators
|
|
;
|
|
; x[1,n] = ( a12 x[1,n-2] + a13 x[1,n-3]) mod m1,
|
|
; x[2,n] = (a21 x[2,n-1] + a23 x[2,n-3]) mod m2,
|
|
;
|
|
; where the constants are
|
|
; m1 = 4294967087 = 2^32 - 209 modulus of 1st component
|
|
; m2 = 4294944443 = 2^32 - 22853 modulus of 2nd component
|
|
; a12 = 1403580 recursion coefficients
|
|
; a13 = -810728
|
|
; a21 = 527612
|
|
; a23 = -1370589
|
|
;
|
|
; The generator passes all tests of G. Marsaglia's Diehard testsuite.
|
|
; Its period is (m1^3 - 1)(m2^3 - 1)/2 which is nearly 2^191.
|
|
; L'Ecuyer reports: "This generator is well-behaved in all dimensions
|
|
; up to at least 45: ..." [with respect to the spectral test, SE].
|
|
;
|
|
; The period is maximal for all values of the seed as long as the
|
|
; state of both recursive generators is not entirely zero.
|
|
;
|
|
; As the successor state is a linear combination of previous
|
|
; states, it is possible to advance the generator by more than one
|
|
; iteration by applying a linear transformation. The following
|
|
; publication provides detailed information on how to do that:
|
|
;
|
|
; [1] P. L'Ecuyer, R. Simard, E. J. Chen, W. D. Kelton:
|
|
; An Object-Oriented Random-Number Package With Many Long
|
|
; Streams and Substreams. 2001.
|
|
; To appear in Operations Research.
|
|
;
|
|
; Arithmetics
|
|
; ===========
|
|
;
|
|
; The MRG32k3a generator produces values in {0..2^32-209-1}. All
|
|
; subexpressions of the actual generator fit into {-2^53..2^53-1}.
|
|
; The code below assumes that Scheme's "integer" covers this range.
|
|
; In addition, it is assumed that floating point literals can be
|
|
; read and there is some arithmetics with inexact numbers.
|
|
;
|
|
; However, for advancing the state of the generator by more than
|
|
; one step at a time, the full range {0..2^32-209-1} is needed.
|
|
|
|
|
|
; Required: Backbone Generator
|
|
; ============================
|
|
;
|
|
; At this point in the code, the following procedures are assumed
|
|
; to be defined to execute the core generator:
|
|
;
|
|
; (mrg32k3a-pack-state unpacked-state) -> packed-state
|
|
; (mrg32k3a-unpack-state packed-state) -> unpacked-state
|
|
; pack/unpack a state of the generator. The core generator works
|
|
; on packed states, passed as an explicit argument, only. This
|
|
; allows native code implementations to store their state in a
|
|
; suitable form. Unpacked states are #(x10 x11 x12 x20 x21 x22)
|
|
; with integer x_ij. Pack/unpack need not allocate new objects
|
|
; in case packed and unpacked states are identical.
|
|
;
|
|
; (mrg32k3a-random-range) -> m-max
|
|
; (mrg32k3a-random-integer packed-state range) -> x in {0..range-1}
|
|
; advance the state of the generator and return the next random
|
|
; range-limited integer.
|
|
; Note that the state is not necessarily advanced by just one
|
|
; step because we use the rejection method to avoid any problems
|
|
; with distribution anomalies.
|
|
; The range argument must be an exact integer in {1..m-max}.
|
|
; It can be assumed that range is a fixnum if the Scheme system
|
|
; has such a number representation.
|
|
;
|
|
; (mrg32k3a-random-real packed-state) -> x in (0,1)
|
|
; advance the state of the generator and return the next random
|
|
; real number between zero and one (both excluded). The type of
|
|
; the result should be a flonum if possible.
|
|
|
|
; Required: Record Data Type
|
|
; ==========================
|
|
;
|
|
; At this point in the code, the following procedures are assumed
|
|
; to be defined to create and access a new record data type:
|
|
;
|
|
; (:random-source-make a0 a1 a2 a3 a4 a5) -> s
|
|
; constructs a new random source object s consisting of the
|
|
; objects a0 .. a5 in this order.
|
|
;
|
|
; (:random-source? obj) -> bool
|
|
; tests if a Scheme object is a :random-source.
|
|
;
|
|
; (:random-source-state-ref s) -> a0
|
|
; (:random-source-state-set! s) -> a1
|
|
; (:random-source-randomize! s) -> a2
|
|
; (:random-source-pseudo-randomize! s) -> a3
|
|
; (:random-source-make-integers s) -> a4
|
|
; (:random-source-make-reals s) -> a5
|
|
; retrieve the values in the fields of the object s.
|
|
|
|
; Required: Current Time as an Integer
|
|
; ====================================
|
|
;
|
|
; At this point in the code, the following procedure is assumed
|
|
; to be defined to obtain a value that is likely to be different
|
|
; for each invokation of the Scheme system:
|
|
;
|
|
; (:random-source-current-time) -> x
|
|
; an integer that depends on the system clock. It is desired
|
|
; that the integer changes as fast as possible.
|
|
|
|
|
|
; Accessing the State
|
|
; ===================
|
|
|
|
(define (mrg32k3a-state-ref packed-state)
|
|
(cons 'lecuyer-mrg32k3a
|
|
(vector->list (mrg32k3a-unpack-state packed-state))))
|
|
|
|
(define (mrg32k3a-state-set external-state)
|
|
|
|
(define (check-value x m)
|
|
(if (and (integer? x)
|
|
(exact? x)
|
|
(<= 0 x (- m 1)))
|
|
#t
|
|
(error "illegal value" x)))
|
|
|
|
(if (and (list? external-state)
|
|
(= (length external-state) 7)
|
|
(eq? (car external-state) 'lecuyer-mrg32k3a))
|
|
(let ((s (cdr external-state)))
|
|
(check-value (list-ref s 0) mrg32k3a-m1)
|
|
(check-value (list-ref s 1) mrg32k3a-m1)
|
|
(check-value (list-ref s 2) mrg32k3a-m1)
|
|
(check-value (list-ref s 3) mrg32k3a-m2)
|
|
(check-value (list-ref s 4) mrg32k3a-m2)
|
|
(check-value (list-ref s 5) mrg32k3a-m2)
|
|
(if (or (zero? (+ (list-ref s 0) (list-ref s 1) (list-ref s 2)))
|
|
(zero? (+ (list-ref s 3) (list-ref s 4) (list-ref s 5))))
|
|
(error "illegal degenerate state" external-state))
|
|
(mrg32k3a-pack-state (list->vector s)))
|
|
(error "malformed state" external-state)))
|
|
|
|
|
|
; Pseudo-Randomization
|
|
; ====================
|
|
;
|
|
; Reference [1] above shows how to obtain many long streams and
|
|
; substream from the backbone generator.
|
|
;
|
|
; The idea is that the generator is a linear operation on the state.
|
|
; Hence, we can express this operation as a 3x3-matrix acting on the
|
|
; three most recent states. Raising the matrix to the k-th power, we
|
|
; obtain the operation to advance the state by k steps at once. The
|
|
; virtual streams and substreams are now simply parts of the entire
|
|
; periodic sequence (which has period around 2^191).
|
|
;
|
|
; For the implementation it is necessary to compute with matrices in
|
|
; the ring (Z/(m1*m1)*Z)^(3x3). By the Chinese-Remainder Theorem, this
|
|
; is isomorphic to ((Z/m1*Z) x (Z/m2*Z))^(3x3). We represent such a pair
|
|
; of matrices
|
|
; [ [[x00 x01 x02],
|
|
; [x10 x11 x12],
|
|
; [x20 x21 x22]], mod m1
|
|
; [[y00 y01 y02],
|
|
; [y10 y11 y12],
|
|
; [y20 y21 y22]] mod m2]
|
|
; as a vector of length 18 of the integers as writen above:
|
|
; #(x00 x01 x02 x10 x11 x12 x20 x21 x22
|
|
; y00 y01 y02 y10 y11 y12 y20 y21 y22)
|
|
;
|
|
; As the implementation should only use the range {-2^53..2^53-1}, the
|
|
; fundamental operation (x*y) mod m, where x, y, m are nearly 2^32,
|
|
; is computed by breaking up x and y as x = x1*w + x0 and y = y1*w + y0
|
|
; where w = 2^16. In this case, all operations fit the range because
|
|
; w^2 mod m is a small number. If proper multiprecision integers are
|
|
; available this is not necessary, but pseudo-randomize! is an expected
|
|
; to be called only occasionally so we do not provide this implementation.
|
|
|
|
(define mrg32k3a-m1 4294967087) ; modulus of component 1
|
|
(define mrg32k3a-m2 4294944443) ; modulus of component 2
|
|
|
|
(define mrg32k3a-initial-state ; 0 3 6 9 12 15 of A^16, see below
|
|
'#( 1062452522
|
|
2961816100
|
|
342112271
|
|
2854655037
|
|
3321940838
|
|
3542344109))
|
|
|
|
(define mrg32k3a-generators #f) ; computed when needed
|
|
|
|
(define (mrg32k3a-pseudo-randomize-state i j)
|
|
|
|
(define (product A B) ; A*B in ((Z/m1*Z) x (Z/m2*Z))^(3x3)
|
|
|
|
(define w 65536) ; wordsize to split {0..2^32-1}
|
|
(define w-sqr1 209) ; w^2 mod m1
|
|
(define w-sqr2 22853) ; w^2 mod m2
|
|
|
|
(define (lc i0 i1 i2 j0 j1 j2 m w-sqr) ; linear combination
|
|
(let ((a0h (quotient (vector-ref A i0) w))
|
|
(a0l (modulo (vector-ref A i0) w))
|
|
(a1h (quotient (vector-ref A i1) w))
|
|
(a1l (modulo (vector-ref A i1) w))
|
|
(a2h (quotient (vector-ref A i2) w))
|
|
(a2l (modulo (vector-ref A i2) w))
|
|
(b0h (quotient (vector-ref B j0) w))
|
|
(b0l (modulo (vector-ref B j0) w))
|
|
(b1h (quotient (vector-ref B j1) w))
|
|
(b1l (modulo (vector-ref B j1) w))
|
|
(b2h (quotient (vector-ref B j2) w))
|
|
(b2l (modulo (vector-ref B j2) w)))
|
|
(modulo
|
|
(+ (* (+ (* a0h b0h)
|
|
(* a1h b1h)
|
|
(* a2h b2h))
|
|
w-sqr)
|
|
(* (+ (* a0h b0l)
|
|
(* a0l b0h)
|
|
(* a1h b1l)
|
|
(* a1l b1h)
|
|
(* a2h b2l)
|
|
(* a2l b2h))
|
|
w)
|
|
(* a0l b0l)
|
|
(* a1l b1l)
|
|
(* a2l b2l))
|
|
m)))
|
|
|
|
(vector
|
|
(lc 0 1 2 0 3 6 mrg32k3a-m1 w-sqr1) ; (A*B)_00 mod m1
|
|
(lc 0 1 2 1 4 7 mrg32k3a-m1 w-sqr1) ; (A*B)_01
|
|
(lc 0 1 2 2 5 8 mrg32k3a-m1 w-sqr1)
|
|
(lc 3 4 5 0 3 6 mrg32k3a-m1 w-sqr1) ; (A*B)_10
|
|
(lc 3 4 5 1 4 7 mrg32k3a-m1 w-sqr1)
|
|
(lc 3 4 5 2 5 8 mrg32k3a-m1 w-sqr1)
|
|
(lc 6 7 8 0 3 6 mrg32k3a-m1 w-sqr1)
|
|
(lc 6 7 8 1 4 7 mrg32k3a-m1 w-sqr1)
|
|
(lc 6 7 8 2 5 8 mrg32k3a-m1 w-sqr1)
|
|
(lc 9 10 11 9 12 15 mrg32k3a-m2 w-sqr2) ; (A*B)_00 mod m2
|
|
(lc 9 10 11 10 13 16 mrg32k3a-m2 w-sqr2)
|
|
(lc 9 10 11 11 14 17 mrg32k3a-m2 w-sqr2)
|
|
(lc 12 13 14 9 12 15 mrg32k3a-m2 w-sqr2)
|
|
(lc 12 13 14 10 13 16 mrg32k3a-m2 w-sqr2)
|
|
(lc 12 13 14 11 14 17 mrg32k3a-m2 w-sqr2)
|
|
(lc 15 16 17 9 12 15 mrg32k3a-m2 w-sqr2)
|
|
(lc 15 16 17 10 13 16 mrg32k3a-m2 w-sqr2)
|
|
(lc 15 16 17 11 14 17 mrg32k3a-m2 w-sqr2)))
|
|
|
|
(define (power A e) ; A^e
|
|
(cond
|
|
((zero? e)
|
|
'#(1 0 0 0 1 0 0 0 1 1 0 0 0 1 0 0 0 1))
|
|
((= e 1)
|
|
A)
|
|
((even? e)
|
|
(power (product A A) (quotient e 2)))
|
|
(else
|
|
(product (power A (- e 1)) A))))
|
|
|
|
(define (power-power A b) ; A^(2^b)
|
|
(if (zero? b)
|
|
A
|
|
(power-power (product A A) (- b 1))))
|
|
|
|
(define A ; the MRG32k3a recursion
|
|
'#( 0 1403580 4294156359
|
|
1 0 0
|
|
0 1 0
|
|
527612 0 4293573854
|
|
1 0 0
|
|
0 1 0))
|
|
|
|
; check arguments
|
|
(if (not (and (integer? i)
|
|
(exact? i)
|
|
(integer? j)
|
|
(exact? j)))
|
|
(error "i j must be exact integer" i j))
|
|
|
|
; precompute A^(2^127) and A^(2^76) only once
|
|
|
|
(if (not mrg32k3a-generators)
|
|
(set! mrg32k3a-generators
|
|
(list (power-power A 127)
|
|
(power-power A 76)
|
|
(power A 16))))
|
|
|
|
; compute M = A^(16 + i*2^127 + j*2^76)
|
|
(let ((M (product
|
|
(list-ref mrg32k3a-generators 2)
|
|
(product
|
|
(power (list-ref mrg32k3a-generators 0)
|
|
(modulo i (expt 2 28)))
|
|
(power (list-ref mrg32k3a-generators 1)
|
|
(modulo j (expt 2 28)))))))
|
|
(mrg32k3a-pack-state
|
|
(vector
|
|
(vector-ref M 0)
|
|
(vector-ref M 3)
|
|
(vector-ref M 6)
|
|
(vector-ref M 9)
|
|
(vector-ref M 12)
|
|
(vector-ref M 15)))))
|
|
|
|
; True Randomization
|
|
; ==================
|
|
;
|
|
; The value obtained from the system time is feed into a very
|
|
; simple pseudo random number generator. This in turn is used
|
|
; to obtain numbers to randomize the state of the MRG32k3a
|
|
; generator, avoiding period degeneration.
|
|
|
|
(define (mrg32k3a-randomize-state state)
|
|
|
|
; G. Marsaglia's simple 16-bit generator with carry
|
|
(define m 65536)
|
|
(define x (modulo (:random-source-current-time) m))
|
|
(define (random-m)
|
|
(let ((y (modulo x m)))
|
|
(set! x (+ (* 30903 y) (quotient x m)))
|
|
y))
|
|
(define (random n) ; m < n < m^2
|
|
(modulo (+ (* (random-m) m) (random-m)) n))
|
|
|
|
; modify the state
|
|
(let ((m1 mrg32k3a-m1)
|
|
(m2 mrg32k3a-m2)
|
|
(s (mrg32k3a-unpack-state state)))
|
|
(mrg32k3a-pack-state
|
|
(vector
|
|
(+ 1 (modulo (+ (vector-ref s 0) (random (- m1 1))) (- m1 1)))
|
|
(modulo (+ (vector-ref s 1) (random m1)) m1)
|
|
(modulo (+ (vector-ref s 2) (random m1)) m1)
|
|
(+ 1 (modulo (+ (vector-ref s 3) (random (- m2 1))) (- m2 1)))
|
|
(modulo (+ (vector-ref s 4) (random m2)) m2)
|
|
(modulo (+ (vector-ref s 5) (random m2)) m2)))))
|
|
|
|
|
|
; Large Integers
|
|
; ==============
|
|
;
|
|
; To produce large integer random deviates, for n > m-max, we first
|
|
; construct large random numbers in the range {0..m-max^k-1} for some
|
|
; k such that m-max^k >= n and then use the rejection method to choose
|
|
; uniformly from the range {0..n-1}.
|
|
|
|
(define mrg32k3a-m-max
|
|
(mrg32k3a-random-range))
|
|
|
|
(define (mrg32k3a-random-power state k) ; n = m-max^k, k >= 1
|
|
(if (= k 1)
|
|
(mrg32k3a-random-integer state mrg32k3a-m-max)
|
|
(+ (* (mrg32k3a-random-power state (- k 1)) mrg32k3a-m-max)
|
|
(mrg32k3a-random-integer state mrg32k3a-m-max))))
|
|
|
|
(define (mrg32k3a-random-large state n) ; n > m-max
|
|
(do ((k 2 (+ k 1))
|
|
(mk (* mrg32k3a-m-max mrg32k3a-m-max) (* mk mrg32k3a-m-max)))
|
|
((>= mk n)
|
|
(let* ((mk-by-n (quotient mk n))
|
|
(a (* mk-by-n n)))
|
|
(do ((x (mrg32k3a-random-power state k)
|
|
(mrg32k3a-random-power state k)))
|
|
((< x a) (quotient x mk-by-n)))))))
|
|
|
|
|
|
; Multiple Precision Reals
|
|
; ========================
|
|
;
|
|
; To produce multiple precision reals we produce a large integer value
|
|
; and convert it into a real value. This value is then normalized.
|
|
; The precision goal is unit <= 1/(m^k + 1), or 1/unit - 1 <= m^k.
|
|
; If you know more about the floating point number types of the
|
|
; Scheme system, this can be improved.
|
|
|
|
(define (mrg32k3a-random-real-mp state unit)
|
|
(do ((k 1 (+ k 1))
|
|
(u (- (/ 1 unit) 1) (/ u mrg32k3a-m1)))
|
|
((<= u 1)
|
|
(/ (exact->inexact (+ (mrg32k3a-random-power state k) 1))
|
|
(exact->inexact (+ (expt mrg32k3a-m-max k) 1))))))
|
|
|
|
|
|
; Provide the Interface as Specified in the SRFI
|
|
; ==============================================
|
|
;
|
|
; An object of type random-source is a record containing the procedures
|
|
; as components. The actual state of the generator is stored in the
|
|
; binding-time environment of make-random-source.
|
|
|
|
(define (make-random-source)
|
|
(let ((state (mrg32k3a-pack-state ; make a new copy
|
|
(list->vector (vector->list mrg32k3a-initial-state)))))
|
|
(:random-source-make
|
|
(lambda ()
|
|
(mrg32k3a-state-ref state))
|
|
(lambda (new-state)
|
|
(set! state (mrg32k3a-state-set new-state)))
|
|
(lambda ()
|
|
(set! state (mrg32k3a-randomize-state state)))
|
|
(lambda (i j)
|
|
(set! state (mrg32k3a-pseudo-randomize-state i j)))
|
|
(lambda ()
|
|
(lambda (n)
|
|
(cond
|
|
((not (and (integer? n) (exact? n) (positive? n)))
|
|
(error "range must be exact positive integer" n))
|
|
((<= n mrg32k3a-m-max)
|
|
(mrg32k3a-random-integer state n))
|
|
(else
|
|
(mrg32k3a-random-large state n)))))
|
|
(lambda args
|
|
(cond
|
|
((null? args)
|
|
(lambda ()
|
|
(mrg32k3a-random-real state)))
|
|
((null? (cdr args))
|
|
(let ((unit (car args)))
|
|
(cond
|
|
((not (and (real? unit) (< 0 unit 1)))
|
|
(error "unit must be real in (0,1)" unit))
|
|
((<= (- (/ 1 unit) 1) mrg32k3a-m1)
|
|
(lambda ()
|
|
(mrg32k3a-random-real state)))
|
|
(else
|
|
(lambda ()
|
|
(mrg32k3a-random-real-mp state unit))))))
|
|
(else
|
|
(error "illegal arguments" args)))))))
|
|
|
|
(define random-source?
|
|
:random-source?)
|
|
|
|
(define (random-source-state-ref s)
|
|
((:random-source-state-ref s)))
|
|
|
|
(define (random-source-state-set! s state)
|
|
((:random-source-state-set! s) state))
|
|
|
|
(define (random-source-randomize! s)
|
|
((:random-source-randomize! s)))
|
|
|
|
(define (random-source-pseudo-randomize! s i j)
|
|
((:random-source-pseudo-randomize! s) i j))
|
|
|
|
; ---
|
|
|
|
(define (random-source-make-integers s)
|
|
((:random-source-make-integers s)))
|
|
|
|
(define (random-source-make-reals s . unit)
|
|
(apply (:random-source-make-reals s) unit))
|
|
|
|
; ---
|
|
|
|
(define default-random-source
|
|
(make-random-source))
|
|
|
|
(define random-integer
|
|
(random-source-make-integers default-random-source))
|
|
|
|
(define random-real
|
|
(random-source-make-reals default-random-source))
|