Clarified the assertion a little more by making the code follow the definition in the wiki more closely.

Author: hemalvarambhia

src/Math-Tests-Matrix/PMQRTest.class.st

@@ -5,14 +5,20 @@ Class {
 }
 
 { #category : #running }
-PMQRTest >> assert: inverse isInverseOf: aMatrix [
-	"A~ * A = A * A~ = I"
+PMQRTest >> assert: inverse isMoorePenroseInverseOf: aMatrix [
+	"https://en.wikipedia.org/wiki/Moore–Penrose_inverse#Definition"
 
 	| identityMatrix |
-	identityMatrix := inverse * aMatrix.
-	self assert: (aMatrix * identityMatrix closeTo: aMatrix).
-	self assert: identityMatrix * inverse closeTo: inverse.
-	self assert: identityMatrix transpose closeTo: identityMatrix.
+	"These two assertions are what define a pseudoinverse. They are known as
+	the Moore–Penrose conditions of which there are four, but here we have two. The other two
+	are that (A * A+) and A+ * A are Hermitian.
+	"
+	self assert: (aMatrix * inverse * aMatrix closeTo: aMatrix).
+	self assert: inverse * aMatrix * inverse closeTo: inverse.
+	
+	"Pseudoinversion commutes with transposition, complex conjugation, and taking the conjugate transpose"
+	self assert: aMatrix transpose mpInverse closeTo: aMatrix mpInverse transpose.
+	
 	identityMatrix := aMatrix * inverse.
 	self assert: identityMatrix transpose closeTo: identityMatrix.
 	self assert: (identityMatrix * aMatrix) closeTo: aMatrix.
@@ -23,7 +29,7 @@ PMQRTest >> mpTestFunction: aMatrix [
 
 	| inverse |
 	inverse := aMatrix mpInverse.
-	self assert: inverse isInverseOf: aMatrix.
+	self assert: inverse isMoorePenroseInverseOf: aMatrix.
 
 ]