68 lines
2.5 KiB
Plaintext
68 lines
2.5 KiB
Plaintext
REFERENCE IMPLEMENTATIONS FOR SRFI-27 "Sources of Random Bits"
|
|
==============================================================
|
|
|
|
Sebastian.Egner@philips.com, 10-Apr-2002.
|
|
|
|
Files
|
|
-----
|
|
|
|
readme - this file
|
|
mrg32k3a.scm - generic parts of P. L' Ecuyer's MRG32k3a PRGN
|
|
mrg32k3a-a.scm - core generator in Scheme integers
|
|
mrg32k3a-b.c - core generator in C doubles for Scheme 48
|
|
mrg32k3a-c.scm - core generator in Gambit [Scheme] flonums
|
|
srfi-27-a.scm - Scheme 48 package definition for Scheme-only impl.
|
|
srfi-27-b.scm - Scheme 48 package definition for C/Scheme impl.
|
|
srfi-27-c.scm - Gambit definition for Scheme-only impl.
|
|
conftest.scm - confidence tests for the implementation
|
|
|
|
Implementations
|
|
---------------
|
|
|
|
The implementation has been factored into three parts.
|
|
One part implements the core generator, one part provides
|
|
the more generic functionality as specified in the SRFI,
|
|
and one part combines the parts and provides the interface
|
|
as specified in the SRFI.
|
|
|
|
a) A Scheme-only implementation for Scheme 48 0.57:
|
|
srfi-27-a.scm
|
|
mrg32k3a-a.scm
|
|
mrg32k3a.scm
|
|
|
|
This implementation uses 54-bit Scheme integers for all
|
|
arithmetics of the generator. The result are Scheme integers
|
|
and inexact Scheme numbers when floating point values are
|
|
requested.
|
|
|
|
The implementation is slow but tries to stay away from
|
|
unportable features as much as possible.
|
|
|
|
b) An implementation in Scheme 48 0.57 and ANSI-C:
|
|
srfi-27-b.scm
|
|
mrg32k3a-b.scm
|
|
mrg32k3a.scm
|
|
|
|
This is a more realistic implementation using C's (double)
|
|
datatype for the core generator and 54-bit Scheme integers
|
|
for the more infrequent operations on the state like the
|
|
random-source-pseudo-randomize! operation.
|
|
|
|
This implementation is meant as an example for a realistic
|
|
native code implementation of the SRFI. Performance is good.
|
|
|
|
c) A Scheme-only implementation for Gambit 3.0:
|
|
srfi-27-c.scm
|
|
mrg32k3a-c.scm
|
|
mrg32k3a.scm
|
|
|
|
This implementation uses Gambit's 64-bit flonums. It is
|
|
entirely written in Scheme but uses a few special features
|
|
of the Gambit system to tell the compiler.
|
|
|
|
This implementation is meant as an example for a realistic
|
|
Scheme implementation using flonums in Scheme and no C-code.
|
|
Performance is good when the code is used in compiled form;
|
|
the implementation has been optimized by Brad Lucier. This
|
|
has resulted in a subtantial performance gain.
|