kurtosis, skewness and variance are not defined on Cauchy distribution

Author: SergeStinckwich

src/Math-Numerical/PMCauchyDistribution.class.st

@@ -65,6 +65,11 @@ PMCauchyDistribution >> initialize: aNumber1 scale: aNumber2 [
 	beta := aNumber2
 ]
 
+{ #category : #information }
+PMCauchyDistribution >> kurtosis [
+self shouldNotImplement 
+]
+
 { #category : #information }
 PMCauchyDistribution >> parameters [
 
@@ -81,6 +86,12 @@ PMCauchyDistribution >> privateInverseDistributionValue: aNumber [
 			ifFalse:[( ( aNumber - (1 / 2)) * Float pi) tan * beta + mu]].
 ]
 
+{ #category : #information }
+PMCauchyDistribution >> skewness [ 
+
+self shouldNotImplement 
+]
+
 { #category : #information }
 PMCauchyDistribution >> standardDeviation [
 	"The standard deviation of the receiver is not defined."
@@ -107,5 +118,6 @@ PMCauchyDistribution >> valueAndGradient: aNumber [
 { #category : #information }
 PMCauchyDistribution >> variance [
 	"The variance of the receiver is not defined."
-	^nil
+
+	self shouldNotImplement 
 ]