handle special case for single value matrix

Author: DurieuxPol

src/Math-Matrix/PMMatrix.class.st

@@ -498,6 +498,8 @@ PMMatrix >> eigen [
 	matrix eigen values.
 	matrix eigen vectors."
 
+	self numberOfColumns == 1 & self numberOfRows == 1 ifTrue: [ ^ PMSingleValueMatrixHelper matrix: self ].
+
 	self isSymmetric
 		ifTrue: [ ^ self asSymmetricMatrix eigen ]
 		ifFalse: [ self error: 'Eigenvalues and eigenvectors of non-symmetric matrix are currently not supported' ]

src/Math-Matrix/PMSingleValueMatrixHelper.class.st

@@ -0,0 +1,13 @@
+Class {
+	#name : 'PMSingleValueMatrixHelper',
+	#superclass : 'PMJacobiTransformationHelper',
+	#category : 'Math-Matrix',
+	#package : 'Math-Matrix'
+}
+
+{ #category : 'initialization' }
+PMSingleValueMatrixHelper >> initialize: aSingleValueMatrix [
+
+	eigenvalues := Array with: (aSingleValueMatrix at: 1 at: 1).
+	eigenvectors := PMVector with: (PMVector ones: 1)
+]