[Issue 105] Math-Random Package Is Messy - Improve Naming, Refactor Tests

src/Math-Random/PMBinomialGenerator.class.st

@@ -21,6 +21,11 @@ PMBinomialGenerator class >> numberOfTrials: numberOfTrials probabilityOfSuccess
 		yourself
 ]
 
+{ #category : #accessing }
+PMBinomialGenerator >> expectedValue [
+	^ numberOfTrials * probability .
+]
+
 { #category : #initialization }
 PMBinomialGenerator >> initialize [
 	self generator: PMParkMillerMinimumRandomGenerator new.

src/Math-Random/PMLehmerRandomGenerator.class.st

@@ -5,7 +5,7 @@ PMLehmerRandomGenerator new next
 "
 Class {
 	#name : #PMLehmerRandomGenerator,
-	#superclass : #PMRandomGenerator,
+	#superclass : #PMPseudoRandomNumberGenerator,
 	#category : #'Math-Random'
 }
 

src/Math-Random/PMLinearCongruentialRandomGenerator.class.st

@@ -5,7 +5,7 @@ PMLinearCongruentialRandomGenerator new next.
 "
 Class {
 	#name : #PMLinearCongruentialRandomGenerator,
-	#superclass : #PMRandomGenerator,
+	#superclass : #PMPseudoRandomNumberGenerator,
 	#category : #'Math-Random'
 }
 

src/Math-Random/PMMarsagliaKissRandom.class.st → src/Math-Random/PMMarsagliaKissRandomGenerator.class.st

@@ -10,8 +10,8 @@ Instance Variables
 
 "
 Class {
-	#name : #PMMarsagliaKissRandom,
-	#superclass : #PMRandomGenerator,
+	#name : #PMMarsagliaKissRandomGenerator,
+	#superclass : #PMPseudoRandomNumberGenerator,
 	#instVars : [
 		'kernelRand1',
 		'kernelRand2'
@@ -20,20 +20,20 @@ Class {
 }
 
 { #category : #'instance creation' }
-PMMarsagliaKissRandom class >> default [
+PMMarsagliaKissRandomGenerator class >> default [
 	^self seed: #(
 		123456789 362436069 521288629 316191069
 		987654321 458629013 582859209 438195021)
 ]
 
 { #category : #'instance creation' }
-PMMarsagliaKissRandom class >> new [
+PMMarsagliaKissRandomGenerator class >> new [
 
 	^ self seed: (PMMarsagliaKissRandomKernel new next: 8)
 ]
 
 { #category : #'stream access' }
-PMMarsagliaKissRandom >> next [
+PMMarsagliaKissRandomGenerator >> next [
 	"Answer a Float in interval [0.0,1.0) with uniform distribution.
 	Note that constant 16rFFFFF800 is computed so as to truncate the 64 bits to Float precision.
 	It is thus ((1 << 32 - 1 << (64 - Float precision) bitAnd: 1 << 32 - 1)) hex"
@@ -42,23 +42,23 @@ PMMarsagliaKissRandom >> next [
 ]
 
 { #category : #'stream access' }
-PMMarsagliaKissRandom >> peek [
+PMMarsagliaKissRandomGenerator >> peek [
 	^self copy next
 ]
 
 { #category : #copying }
-PMMarsagliaKissRandom >> postCopy [
+PMMarsagliaKissRandomGenerator >> postCopy [
 	kernelRand1 := kernelRand1 copy.
 	kernelRand2 := kernelRand2 copy
 ]
 
 { #category : #accessing }
-PMMarsagliaKissRandom >> seed [
+PMMarsagliaKissRandomGenerator >> seed [
 	^ kernelRand1 seed , kernelRand2 seed
 ]
 
 { #category : #accessing }
-PMMarsagliaKissRandom >> seed: aWordArray [
+PMMarsagliaKissRandomGenerator >> seed: aWordArray [
 	"Initialize with an Array of eight 32-bits Integer"
 	kernelRand1 := PMMarsagliaKissRandomKernel seed: (aWordArray first: 4).
 	kernelRand2 := PMMarsagliaKissRandomKernel seed: (aWordArray last: 4)

src/Math-Random/PMMersenneTwisterRandomGenerator.class.st

@@ -11,7 +11,7 @@ MersenneTwisterRandom new nextInteger.
 "
 Class {
 	#name : #PMMersenneTwisterRandomGenerator,
-	#superclass : #PMRandomGenerator,
+	#superclass : #PMPseudoRandomNumberGenerator,
 	#instVars : [
 		'states',
 		'mti'
@@ -26,7 +26,7 @@ Class {
 		'TemperingMaskB',
 		'TemperingMaskC'
 	],
-	#category : 'Math-Random'
+	#category : #'Math-Random'
 }
 
 { #category : #'class initialization' }

src/Math-Random/PMParkMillerMinimumRandomGenerator.class.st

@@ -5,7 +5,7 @@ PMParkMillerMinimumRandomGenerator new next
 "
 Class {
 	#name : #PMParkMillerMinimumRandomGenerator,
-	#superclass : #PMRandomGenerator,
+	#superclass : #PMPseudoRandomNumberGenerator,
 	#category : #'Math-Random'
 }
 

src/Math-Random/PMRandomGenerator.class.st → src/Math-Random/PMPseudoRandomNumberGenerator.class.st

@@ -31,16 +31,16 @@ And finally, there's a taxonomy more related with the internal implementation, b
 
 "
 Class {
-	#name : #PMRandomGenerator,
+	#name : #PMPseudoRandomNumberGenerator,
 	#superclass : #Object,
 	#instVars : [
 		'seed'
 	],
-	#category : 'Math-Random'
+	#category : #'Math-Random'
 }
 
 { #category : #testing }
-PMRandomGenerator class >> chiSquare: range repeating: anInteger [
+PMPseudoRandomNumberGenerator class >> chiSquare: range repeating: anInteger [
 	"Run a 'chi-square' test on a random number generator, over a range of integers given by range, repeating anInteger times.  
     Answer an Array containing the result of the chi-square test (which should be the same as the range), and the upper and lower bounds for 'good' randomness (assuming that anInteger is at least 10 * range)."
 
@@ -64,29 +64,29 @@ PMRandomGenerator class >> chiSquare: range repeating: anInteger [
 ]
 
 { #category : #'instance creation' }
-PMRandomGenerator class >> new [
+PMPseudoRandomNumberGenerator class >> new [
 	"Answer a new instance of the receiver"
 
 	^ (self seed: Time millisecondClockValue) initialize
 ]
 
 { #category : #'instance creation' }
-PMRandomGenerator class >> seed: anInteger [
+PMPseudoRandomNumberGenerator class >> seed: anInteger [
 	"Anwer a new Random stream with the initial seed anInteger."
 
 	^ self basicNew seed: anInteger; yourself
 ]
 
 { #category : #testing }
-PMRandomGenerator >> atEnd [
+PMPseudoRandomNumberGenerator >> atEnd [
 	"Answer whether the receiver is at its end - never true for a stream of Random numbers"
 
 	^ false
 
 ]
 
 { #category : #accessing }
-PMRandomGenerator >> contents [
+PMPseudoRandomNumberGenerator >> contents [
 	"Answer all of the objects in the collection accessed by the receiver.
 	Implementation Notes: Random streams are infinite, so there is no implementation possible."
 
@@ -95,52 +95,52 @@ PMRandomGenerator >> contents [
 ]
 
 { #category : #testing }
-PMRandomGenerator >> isReadable [
+PMPseudoRandomNumberGenerator >> isReadable [
 	"Answer whether the receiver can be read from (i.e. it implements the gettableStream protocol)."
 
 	^ true
 
 ]
 
 { #category : #testing }
-PMRandomGenerator >> isWriteable [
+PMPseudoRandomNumberGenerator >> isWriteable [
 	"Answer whether the receiver can be written to (i.e. it implements the puttableStream protocol)."
 
 	^ false
 
 ]
 
 { #category : #'stream access' }
-PMRandomGenerator >> next [
+PMPseudoRandomNumberGenerator >> next [
  	"Answer a pseudo-Random number"
 
 	^ self subclassResponsibility
 ]
 
 { #category : #'stream access' }
-PMRandomGenerator >> next: anInteger [
+PMPseudoRandomNumberGenerator >> next: anInteger [
 	"Answer a collection of size anInteger of pseudo-random Floats between 0 and 1. "
 
 	^ ( 1 to: anInteger ) collect: [ :i | self next ]
 
 ]
 
 { #category : #'stream access' }
-PMRandomGenerator >> peek [
+PMPseudoRandomNumberGenerator >> peek [
 	"Answer a pseudo-Random number generated from the next seed,  but do not advance down the stream (i.e. self peek = self peek). "
 
 	^ self subclassResponsibility
 ]
 
 { #category : #accessing }
-PMRandomGenerator >> seed [
+PMPseudoRandomNumberGenerator >> seed [
     "Returns the instance var of the receiver for external manipulation"
 
     ^ seed
 ]
 
 { #category : #accessing }
-PMRandomGenerator >> seed: anObject [
+PMPseudoRandomNumberGenerator >> seed: anObject [
     "Sets the instance var of the receiver with anObject. (No checking is done)"
 
     seed := anObject

src/Math-Tests-Random/PMBernoulliGeneratorTest.class.st

@@ -7,17 +7,6 @@ Class {
 	#category : #'Math-Tests-Random'
 }
 
-{ #category : #tests }
-PMBernoulliGeneratorTest >> testGenerator [
-	| g bern |
-	g := PMLinearCongruentialRandomGenerator new.
-	bern := PMBernoulliGenerator new.
-	self
-		assert: (bern generator isKindOf: PMBernoulliGenerator defaultGeneratorClass).
-	bern generator: g.
-	self assert: (bern generator isKindOf: PMLinearCongruentialRandomGenerator)
-]
-
 { #category : #tests }
 PMBernoulliGeneratorTest >> testNextYieldsOneOrZero [
 	| gen |

src/Math-Tests-Random/PMBinomialGeneratorTest.class.st

@@ -4,27 +4,6 @@ Class {
 	#category : #'Math-Tests-Random'
 }
 
-{ #category : #tests }
-PMBinomialGeneratorTest >> testBinomialGeneratorConvergesToMean [
-	"Its purpose is to verify correct convergence of the binomial distribution, 
-	should be Normal (np, np(1-p))"
-
-	| gen nums mean probabilityOfSuccess numberOfTrials |
-	probabilityOfSuccess := (Random seed: 0.0) next sqrt.
-	numberOfTrials := 1000.
-	gen := PMBinomialGenerator
-		numberOfTrials: numberOfTrials
-		probabilityOfSuccess: probabilityOfSuccess.
-
-	nums := OrderedCollection new.
-	(1 to: numberOfTrials) do: [ :ea | nums add: gen next ].
-
-	mean := numberOfTrials * probabilityOfSuccess.
-	self assert: nums min > (mean * (1 - 0.2)).
-	self assert: nums max < (mean * (1 + 0.2)).
-	self assert: (nums average - mean) abs < 5
-]
-
 { #category : #tests }
 PMBinomialGeneratorTest >> testBinomialGeneratorWithSuccessProbabilityOfOneAlwaysReturnNumberOfTrials [
 	| g numberOfTrials |
@@ -56,3 +35,23 @@ PMBinomialGeneratorTest >> testBinomialGeneratorWithSuccessProbabilityOfZeroAlwa
 	g generator: PMMersenneTwisterRandomGenerator new.
 	self assert: g next equals: 0
 ]
+
+{ #category : #tests }
+PMBinomialGeneratorTest >> testSampleMeanConvergesToExpectedValue [
+	"Its purpose is to verify correct convergence of the binomial distribution, 
+	should be Normal (np, np(1-p))"
+
+	| gen sample probabilityOfSuccess numberOfTrials |
+	probabilityOfSuccess := (Random seed: 0.0) next sqrt.
+	numberOfTrials := 1000.
+	gen := PMBinomialGenerator
+		numberOfTrials: numberOfTrials
+		probabilityOfSuccess: probabilityOfSuccess.
+
+	sample := OrderedCollection new.
+	numberOfTrials timesRepeat: [ sample add: gen next ].
+
+	self assert: sample min > (gen expectedValue * (1 - 0.2)).
+	self assert: sample max < (gen expectedValue * (1 + 0.2)).
+	self assert: (sample average - gen expectedValue) abs < 5
+]

src/Math-Tests-Random/PMExponentialGeneratorTest.class.st

@@ -13,14 +13,14 @@ PMExponentialGeneratorTest >> testGenerator [
 	eg := PMExponentialGenerator new.
 	self
 		assert: (eg generator isKindOf: PMExponentialGenerator defaultGeneratorClass).
-	self assert: (eg generator isKindOf: PMRandomGenerator).
+	self assert: (eg generator isKindOf: PMPseudoRandomNumberGenerator).
 	eg generator: PMMersenneTwisterRandomGenerator new.
 	self assert: (eg generator isKindOf: PMMersenneTwisterRandomGenerator).
 	self assert: (eg next isKindOf: Number)
 ]
 
 { #category : #tests }
-PMExponentialGeneratorTest >> testPeekAlwaysAnswersTheSame [
+PMExponentialGeneratorTest >> testPeekIsIdempotent [
 	| eg |
 	eg := PMExponentialGenerator new.
 	self assert: eg peek equals: eg peek.
@@ -31,10 +31,11 @@ PMExponentialGeneratorTest >> testPeekAlwaysAnswersTheSame [
 PMExponentialGeneratorTest >> testSampleMeanConvergesToDistributionMean [
 	"testing a random sample seems suspect. We use a 5% interval here"
 
-	| eg arr |
-	eg := PMExponentialGenerator mean: 10.
-	arr := Array new: 10000.
-	arr := arr collect: [ :each | eg next ].
+	| gen sample |
+	gen := PMExponentialGenerator mean: 10.
+	sample := Array new: 10000.
+	sample := sample collect: [ :each | gen next ].
+
 	self
-		assert: (arr average between: eg mean * 0.95 and: eg mean * 1.05)
+		assert: (sample average between: gen mean * 0.95 and: gen mean * 1.05)
 ]

src/Math-Tests-Random/PMLaplaceGeneratorTest.class.st

@@ -4,14 +4,9 @@ Class {
 	#category : #'Math-Tests-Random'
 }
 
-{ #category : #'as yet unclassified' }
-PMLaplaceGeneratorTest >> classToTest [ 
-	^ PMLaplaceGenerator 
-]
-
-{ #category : #accessing }
-PMLaplaceGeneratorTest >> testPeekAlwaysReplyTheSameValue [
+{ #category : #tests }
+PMLaplaceGeneratorTest >> testPeekIsIdempotent [
 	| g |
-	g := self classToTest shape: 0.5 scale: 0.3.
+	g := PMLaplaceGenerator shape: 0.5 scale: 0.3.
 	self assert: g peek equals: g peek
 ]

src/Math-Tests-Random/PMLehmerRandomTest.class.st

@@ -14,15 +14,15 @@ PMLehmerRandomTest >> testNextBetweenZeroAndOne [
 ]
 
 { #category : #tests }
-PMLehmerRandomTest >> testPeekAlwaysReplyTheSameValue [
+PMLehmerRandomTest >> testPeekAnswersSameAsNext [
 	| g |
 	g := PMLehmerRandomGenerator new.
-	self assert: g peek equals: g peek
+	self assert: g peek equals: g next
 ]
 
 { #category : #tests }
-PMLehmerRandomTest >> testPeekAnswersSameAsNext [
+PMLehmerRandomTest >> testPeekIsIdempotent [
 	| g |
 	g := PMLehmerRandomGenerator new.
-	self assert: g peek equals: g next
+	self assert: g peek equals: g peek
 ]

src/Math-Tests-Random/PMLinearCongruentialRandomTest.class.st

@@ -14,15 +14,15 @@ PMLinearCongruentialRandomTest >> testNextBetweenZeroAndOne [
 ]
 
 { #category : #tests }
-PMLinearCongruentialRandomTest >> testPeekAlwaysReplyTheSameValue [
+PMLinearCongruentialRandomTest >> testPeekAnswersSameAsNext [
 	| g |
 	g := PMLinearCongruentialRandomGenerator new.
-	self assert: g peek equals: g peek
+	self assert: g peek equals: g next
 ]
 
 { #category : #tests }
-PMLinearCongruentialRandomTest >> testPeekAnswersSameAsNext [
+PMLinearCongruentialRandomTest >> testPeekIsIdempotent [
 	| g |
 	g := PMLinearCongruentialRandomGenerator new.
-	self assert: g peek equals: g next
+	self assert: g peek equals: g peek
 ]