Is there a fixed seed for the pseudo-random number generator? And what method is used for generating them?
What is the result of
(import (srfi 27))(random-real)or equivalent?
(Evidently, the test is performed several times starting a fresh REPL then exiting, and then starting over...)
Interestingly, some schemes do share both the seed and the method -- because the generated random real is the same for them.
At least in the case of Sagittarius and STklos, that is not due to implementors using the reference implementation of SRFI-27: STklos uses a custom Mersenne Twister generator.
| System | fixed or varies? | value | obs | PRNG method |
|---|---|---|---|---|
| Bigloo | varies | (randomfl) |
||
| Chez | fixed | 0.49980777502645934 | (random 1.0) |
random seed generated from thread context. (c/number.c) |
| Chibi | varies | |||
| Chicken | fixed | 0.857402537562821 | = S48, gambit | Reference implementation of SRFI-27 (based on Pierre Lecuyer's MRG32K3A) |
| Cyclone | varies | Linear Congruential (srfi/27.sld) | ||
| Foment | varies | C++ <random> (src/random.cpp) | ||
| Gambit | fixed | 0.8574025375628211 | = S48, chicken | Reference implementation of SRFI-27 (based on Pierre Lecuyer's MRG32K3A) |
| Gauche | fixed | 0.8147236863931789 | Mersenne Twister | |
| Guile | fixed | 0.8187953998906781 | Multiply With Carry (libguile/random.c); also external? (lib/getrandom.c) | |
| MIT | fixed | 0.9123799209965706 | ChaCha20 (src/runtime/random.scm) | |
| Sagittarius | fixed | 0.7868209548678019 | = STklos | Mersenne Twister (sitelib/srfi/%3a27/random-bits.scm) |
| Scheme48 | fixed | 0.8574025375628211 | = gambit, chicken | |
| STklos | fixed | 0.7868209548678019 | = sagittarius | Mersenne Twister (lib/srfi/27.{stk,c}) |
| Unsyntax | varies | |||
| Ypsilon | varies | Multiply With Carry (sitelib/srfi/27.scm) |