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41 changes: 41 additions & 0 deletions src/Math-Random/PMFishmanMooreRandomGenerator.class.st
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"
I am a simple implementation of Fishman-Moore pseudo-random number generator.

Onghena, P. A theoretical and empirical comparison of mainframe, microcomputer, and pocket calculator pseudorandom number generators. Behavior Research Methods, Instruments, & Computers 25, 384–395 (1993). https://doi.org/10.3758/BF03204529
"
Class {
#name : #PMFishmanMooreRandomGenerator,
#superclass : #PMPseudoRandomNumberGenerator,
#category : #'Math-Random'
}

{ #category : #initialization }
PMFishmanMooreRandomGenerator >> initialize [
super initialize.
seed := Time millisecondClockValue
]

{ #category : #accessing }
PMFishmanMooreRandomGenerator >> next [
^ (seed := 742938285 * seed \\ 2147483647) / 2147483647.0
]

{ #category : #accessing }
PMFishmanMooreRandomGenerator >> nextInt: anInteger [
^ (self next * anInteger) truncated + 1
]

{ #category : #accessing }
PMFishmanMooreRandomGenerator >> peek [
^ 742938285 * seed \\ 2147483647 / 2147483647.0
]

{ #category : #accessing }
PMFishmanMooreRandomGenerator >> seed [
^ seed
]

{ #category : #accessing }
PMFishmanMooreRandomGenerator >> seed: anInteger [
seed := anInteger asInteger
]
16 changes: 16 additions & 0 deletions src/Math-Tests-Random/PMFishmanMooreRandomGeneratorTest.class.st
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Class {
#name : #PMFishmanMooreRandomGeneratorTest,
#superclass : #TestCase,
#category : #'Math-Tests-Random'
}

{ #category : #tests }
PMFishmanMooreRandomGeneratorTest >> testNext [
| random expectedNumbers |
random := PMFishmanMooreRandomGenerator new.
random seed: 2147483646.
expectedNumbers := #(0.6540424017 0.2032902977 0.1634123433 0.0948051145 0.1617738056 0.6769099178 0.4410270808 0.0819611824 0.3259203002 0.9101976547).
(1 to: expectedNumbers size)
with: expectedNumbers
do: [ :i :expected | self assert: random next closeTo: expected ]
]