/usr/share/gnu-smalltalk/kernel/Random.st is in gnu-smalltalk-common 3.2.4-2.1.
This file is owned by root:root, with mode 0o644.
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| Random number Method Definitions
|
|
======================================================================"
"======================================================================
|
| Copyright 1988,92,94,95,99,2000,2001,2002
| Free Software Foundation, Inc.
| Written by Steve Byrne.
|
| This file is part of the GNU Smalltalk class library.
|
| The GNU Smalltalk class library is free software; you can redistribute it
| and/or modify it under the terms of the GNU Lesser General Public License
| as published by the Free Software Foundation; either version 2.1, or (at
| your option) any later version.
|
| The GNU Smalltalk class library is distributed in the hope that it will be
| useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
| General Public License for more details.
|
| You should have received a copy of the GNU Lesser General Public License
| along with the GNU Smalltalk class library; see the file COPYING.LIB.
| If not, write to the Free Software Foundation, 59 Temple Place - Suite
| 330, Boston, MA 02110-1301, USA.
|
======================================================================"
Stream subclass: Random [
| seed |
<category: 'Streams'>
<comment: 'My instances are generator streams that produce random numbers, which are
floating point values between 0 and 1.'>
Random class [
| source |
]
Random class >> seed: aFloat [
"Create a new random number generator whose seed is aFloat"
<category: 'instance creation'>
^(self basicNew)
seed: aFloat;
yourself
]
Random class >> new [
"Create a new random number generator whose seed is given by the
current time on the millisecond clock"
<category: 'instance creation'>
^self basicNew setSeed
]
Random class >> source [
"Return a standard source of random numbers."
<category: 'shortcuts'>
^source isNil ifTrue: [source := self new] ifFalse: [source]
]
Random class >> next [
"Return a random number between 0 and 1 (excluded)"
<category: 'shortcuts'>
^self source next
]
Random class >> between: low and: high [
"Return a random integer between the given extrema"
<category: 'shortcuts'>
^self source between: low and: high
]
chiSquare [
"Compute the chi-square of the random that this class generates."
"the previous algorithm's chi-square was 93.4"
<category: 'testing'>
^self chiSquare: 1000 range: 100
]
chiSquare: n range: r [
"Return the chi-square deduced from calculating n random
numbers in the 0..r range."
<category: 'testing'>
| f t seed |
seed := 0.1234567.
f := Array new: r + 1.
1 to: r + 1 do: [:i | f at: i put: 0].
n timesRepeat:
[seed := (seed + Float pi) squared squared fractionPart.
t := (seed * r) truncated.
f at: t + 1 put: (f at: t + 1) + 1].
t := 0.
1 to: r do: [:i | t := t + (f at: i) squared].
^r asFloat * t / n - n
]
atEnd [
"This stream never ends. Always answer false."
<category: 'basic'>
^false
]
between: low and: high [
"Return a random integer between low and high."
<category: 'basic'>
| i range |
range := high - low + 1.
i := (self next * range) truncated.
^i + low
]
next [
"Return the next random number in the sequence."
"Found on an obscure Japanese manual. Turns out to be good!"
<category: 'basic'>
^seed := (seed + Float pi) squared squared fractionPart
]
nextPut: value [
<category: 'basic'>
self shouldNotImplement
]
seed: aFloat [
"Private - Set the random number seed to aFloat.
Ensure decent results even when integers are passed"
<category: 'private'>
seed := (aFloat / 100000.0 + aFloat) fractionPart.
self next.
self next
]
setSeed [
"Private - Set a random number seed."
<category: 'private'>
seed := Time primSecondClock - Time primMillisecondClock.
seed := (seed / 4194303.0) fractionPart.
self next.
self next
]
]
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