From 5e28302b4f3f5a23cb74d9812f8b51480d49d35c Mon Sep 17 00:00:00 2001
From: hemalvarambhia <h.n.varambhia@gmail.com>
Date: Wed, 7 Sep 2022 21:54:38 +0100
Subject: [PATCH 01/14] Used a message that performs the same logic in its
 method.

---
 src/Math-Matrix/PMQRDecomposition.class.st | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Math-Matrix/PMQRDecomposition.class.st b/src/Math-Matrix/PMQRDecomposition.class.st
index 387542b7..987e8aad 100644
--- a/src/Math-Matrix/PMQRDecomposition.class.st
+++ b/src/Math-Matrix/PMQRDecomposition.class.st
@@ -128,7 +128,7 @@ PMQRDecomposition >> decomposeWithPivot [
 		i := q numberOfColumns - i.
 		pivot := pivot copyFrom: 1 to: i.
 		q := PMMatrix rows:
-			     (q rows collect: [ :row | row copyFrom: 1 to: i ]) ].
+			     (q rowsCollect: [ :row | row copyFrom: 1 to: i ]) ].
 	^ Array with: q with: r with: pivot
 ]
 

From 5c09925155ec840c0fabb902f2dc50290451286a Mon Sep 17 00:00:00 2001
From: hemalvarambhia <h.n.varambhia@gmail.com>
Date: Wed, 7 Sep 2022 21:55:26 +0100
Subject: [PATCH 02/14] Performed the same refactoring in the pivot message's
 method.

---
 src/Math-Matrix/PMQRDecomposition.class.st | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Math-Matrix/PMQRDecomposition.class.st b/src/Math-Matrix/PMQRDecomposition.class.st
index 987e8aad..fad41fc7 100644
--- a/src/Math-Matrix/PMQRDecomposition.class.st
+++ b/src/Math-Matrix/PMQRDecomposition.class.st
@@ -61,7 +61,7 @@ https://en.wikipedia.org/wiki/QR_decomposition#Using_Householder_reflections
 		r := PMMatrix rows: (r rows copyFrom: 1 to: colSize).
 		i := q numberOfColumns - i.
 		q := PMMatrix rows:
-			     (q rows collect: [ :row | row copyFrom: 1 to: i ]) ].
+			     (q rowsCollect: [ :row | row copyFrom: 1 to: i ]) ].
 	^ Array with: q with: r
 ]
 

From 3a04d724e3dce576320a553b7593bf38452b804a Mon Sep 17 00:00:00 2001
From: hemalvarambhia <h.n.varambhia@gmail.com>
Date: Wed, 7 Sep 2022 22:01:50 +0100
Subject: [PATCH 03/14] Extracted duplicate code to an intention revealing
 message and method.

---
 src/Math-Matrix/PMQRDecomposition.class.st | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/Math-Matrix/PMQRDecomposition.class.st b/src/Math-Matrix/PMQRDecomposition.class.st
index fad41fc7..868a34d8 100644
--- a/src/Math-Matrix/PMQRDecomposition.class.st
+++ b/src/Math-Matrix/PMQRDecomposition.class.st
@@ -58,7 +58,7 @@ https://en.wikipedia.org/wiki/QR_decomposition#Using_Householder_reflections
 		i := i + 1.
 		colSize := colSize - 1 ].
 	i > 0 ifTrue: [ 
-		r := PMMatrix rows: (r rows copyFrom: 1 to: colSize).
+		r := self upperTriangularPartOf: r With: colSize.
 		i := q numberOfColumns - i.
 		q := PMMatrix rows:
 			     (q rowsCollect: [ :row | row copyFrom: 1 to: i ]) ].
@@ -124,7 +124,7 @@ PMQRDecomposition >> decomposeWithPivot [
 		i := i + 1.
 		colSize := colSize - 1 ].
 	i > 0 ifTrue: [ 
-		r := PMMatrix rows: (r rows copyFrom: 1 to: colSize).
+		r := self upperTriangularPartOf: r With: colSize.
 		i := q numberOfColumns - i.
 		pivot := pivot copyFrom: 1 to: i.
 		q := PMMatrix rows:
@@ -158,3 +158,9 @@ PMQRDecomposition >> of: matrix [
 		r := self initialRMatrix.
 	q := self initialQMatrix.
 ]
+
+{ #category : #private }
+PMQRDecomposition >> upperTriangularPartOf: matrix With: columnSize [
+
+	^ PMMatrix rows: (r rows copyFrom: 1 to: columnSize)
+]

From 97bc32bde43fe130517c042cd05d4d963e2a6aab Mon Sep 17 00:00:00 2001
From: hemalvarambhia <h.n.varambhia@gmail.com>
Date: Wed, 7 Sep 2022 22:37:59 +0100
Subject: [PATCH 04/14] Clarified the name of a temporary variable.

---
 src/Math-Matrix/PMQRDecomposition.class.st | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/Math-Matrix/PMQRDecomposition.class.st b/src/Math-Matrix/PMQRDecomposition.class.st
index 868a34d8..3de2c848 100644
--- a/src/Math-Matrix/PMQRDecomposition.class.st
+++ b/src/Math-Matrix/PMQRDecomposition.class.st
@@ -46,13 +46,13 @@ https://en.wikipedia.org/wiki/QR_decomposition#Using_Householder_reflections
 				                  (householderVector at: 1)
 				                  * (householderVector at: 2) * matrixOfMinor).
 		matrixOfMinor rowsWithIndexDo: [ :aRow :index | 
-			aRow withIndexDo: [ :n :c | 
+			aRow withIndexDo: [ :element :c | 
 				r
 					rowAt: col + index - 1
 					columnAt: col + c - 1
-					put: ((n closeTo: 0)
+					put: ((element closeTo: 0)
 							 ifTrue: [ 0 ]
-							 ifFalse: [ n ]) ] ] ].
+							 ifFalse: [ element ]) ] ] ].
 	i := 0.
 	[ (r rowAt: colSize) isZero ] whileTrue: [ 
 		i := i + 1.

From df9874c328f3e934c85baf5f1b3d2dc4b1f3c700 Mon Sep 17 00:00:00 2001
From: hemalvarambhia <h.n.varambhia@gmail.com>
Date: Wed, 7 Sep 2022 22:43:54 +0100
Subject: [PATCH 05/14] Clarified the name of a block variable.

---
 src/Math-Matrix/PMQRDecomposition.class.st | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/Math-Matrix/PMQRDecomposition.class.st b/src/Math-Matrix/PMQRDecomposition.class.st
index 3de2c848..b443ec9d 100644
--- a/src/Math-Matrix/PMQRDecomposition.class.st
+++ b/src/Math-Matrix/PMQRDecomposition.class.st
@@ -46,10 +46,10 @@ https://en.wikipedia.org/wiki/QR_decomposition#Using_Householder_reflections
 				                  (householderVector at: 1)
 				                  * (householderVector at: 2) * matrixOfMinor).
 		matrixOfMinor rowsWithIndexDo: [ :aRow :index | 
-			aRow withIndexDo: [ :element :c | 
+			aRow withIndexDo: [ :element :column | 
 				r
 					rowAt: col + index - 1
-					columnAt: col + c - 1
+					columnAt: col + column - 1
 					put: ((element closeTo: 0)
 							 ifTrue: [ 0 ]
 							 ifFalse: [ element ]) ] ] ].

From 0e2952f8726e7484ecb42a2202c0825b232b4c4c Mon Sep 17 00:00:00 2001
From: hemalvarambhia <h.n.varambhia@gmail.com>
Date: Wed, 7 Sep 2022 22:47:20 +0100
Subject: [PATCH 06/14] Made similar code even more similar.

---
 src/Math-Matrix/PMQRDecomposition.class.st | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/src/Math-Matrix/PMQRDecomposition.class.st b/src/Math-Matrix/PMQRDecomposition.class.st
index b443ec9d..ea4eea86 100644
--- a/src/Math-Matrix/PMQRDecomposition.class.st
+++ b/src/Math-Matrix/PMQRDecomposition.class.st
@@ -47,9 +47,12 @@ https://en.wikipedia.org/wiki/QR_decomposition#Using_Householder_reflections
 				                  * (householderVector at: 2) * matrixOfMinor).
 		matrixOfMinor rowsWithIndexDo: [ :aRow :index | 
 			aRow withIndexDo: [ :element :column | 
+				| rowNumber columnNumber |
+				rowNumber := col + index - 1.
+				columnNumber := col + column - 1.
 				r
-					rowAt: col + index - 1
-					columnAt: col + column - 1
+					rowAt: rowNumber
+					columnAt: columnNumber
 					put: ((element closeTo: 0)
 							 ifTrue: [ 0 ]
 							 ifFalse: [ element ]) ] ] ].
@@ -95,9 +98,12 @@ PMQRDecomposition >> decomposeWithPivot [
 			                  * (householderVector at: 2) * matrixOfMinor).
 	matrixOfMinor rowsWithIndexDo: [ :aRow :index | 
 		aRow withIndexDo: [ :element :column | 
+			| rowNumber columnNumber |
+			rowNumber := rank + index - 1.
+			columnNumber := rank + column - 1.
 			r
-				rowAt: rank + index - 1
-				columnAt: rank + column - 1
+				rowAt: rowNumber
+				columnAt: columnNumber
 				put: ((element closeTo: 0)
 						 ifTrue: [ 0 ]
 						 ifFalse: [ element ]) ] ].

From bc7c95d234e46899baac18b542aca06c946041ce Mon Sep 17 00:00:00 2001
From: hemalvarambhia <h.n.varambhia@gmail.com>
Date: Sun, 11 Sep 2022 13:30:35 +0100
Subject: [PATCH 07/14] Moved the declaration closer to the site of the
 computation.

---
 src/Math-Matrix/PMQRDecomposition.class.st | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/Math-Matrix/PMQRDecomposition.class.st b/src/Math-Matrix/PMQRDecomposition.class.st
index ea4eea86..d8cd6110 100644
--- a/src/Math-Matrix/PMQRDecomposition.class.st
+++ b/src/Math-Matrix/PMQRDecomposition.class.st
@@ -29,13 +29,13 @@ that describes the mechanics:
 https://en.wikipedia.org/wiki/QR_decomposition#Using_Householder_reflections
 "
 
-	| identityMatrix householderVector i matrixOfMinor |
-	identityMatrix := PMSymmetricMatrix identity: colSize.
+	| i matrixOfMinor |
 	1 to: self numberOfColumns do: [ :col | 
-		| columnVectorFromRMatrix householderMatrix v |
+		| householderVector householderMatrix columnVectorFromRMatrix identityMatrix v |
 		columnVectorFromRMatrix := r columnVectorAt: col size: colSize.
 		householderVector := columnVectorFromRMatrix householder.
 		v := (PMVector zeros: col - 1) , (householderVector at: 2).
+		identityMatrix := PMSymmetricMatrix identity: colSize.
 		householderMatrix := identityMatrix
 		                     -
 		                     ((householderVector at: 1) * v tensorProduct: v).

From 1bd05784e043f3a164b444f09f527f1cc3348cac Mon Sep 17 00:00:00 2001
From: hemalvarambhia <h.n.varambhia@gmail.com>
Date: Sun, 11 Sep 2022 13:39:55 +0100
Subject: [PATCH 08/14] Extracted a key computation step to an
 intention-revealing method.

---
 src/Math-Matrix/PMQRDecomposition.class.st | 29 ++++++++++++++++------
 1 file changed, 21 insertions(+), 8 deletions(-)

diff --git a/src/Math-Matrix/PMQRDecomposition.class.st b/src/Math-Matrix/PMQRDecomposition.class.st
index d8cd6110..b2aeced3 100644
--- a/src/Math-Matrix/PMQRDecomposition.class.st
+++ b/src/Math-Matrix/PMQRDecomposition.class.st
@@ -29,16 +29,16 @@ that describes the mechanics:
 https://en.wikipedia.org/wiki/QR_decomposition#Using_Householder_reflections
 "
 
-	| i matrixOfMinor |
+	| i matrixOfMinor householderReflection |
 	1 to: self numberOfColumns do: [ :col | 
-		| householderVector householderMatrix columnVectorFromRMatrix identityMatrix v |
+		| householderVector householderMatrix columnVectorFromRMatrix |
 		columnVectorFromRMatrix := r columnVectorAt: col size: colSize.
-		householderVector := columnVectorFromRMatrix householder.
-		v := (PMVector zeros: col - 1) , (householderVector at: 2).
-		identityMatrix := PMSymmetricMatrix identity: colSize.
-		householderMatrix := identityMatrix
-		                     -
-		                     ((householderVector at: 1) * v tensorProduct: v).
+		householderReflection := self
+			                         householderReflectionOf:
+			                         columnVectorFromRMatrix
+			                         atColumnNumber: col.
+		householderVector := householderReflection at: 1.
+		householderMatrix := householderReflection at: 2.
 		q := q * householderMatrix.
 		matrixOfMinor := r minor: col - 1 and: col - 1.
 		matrixOfMinor := matrixOfMinor
@@ -138,6 +138,19 @@ PMQRDecomposition >> decomposeWithPivot [
 	^ Array with: q with: r with: pivot
 ]
 
+{ #category : #private }
+PMQRDecomposition >> householderReflectionOf: columnVector atColumnNumber: columnNumber [
+
+	| householderVector v identityMatrix householderMatrix |
+	householderVector := columnVector householder.
+	v := (PMVector zeros: columnNumber - 1) , (householderVector at: 2).
+	identityMatrix := PMSymmetricMatrix identity: colSize.
+	householderMatrix := identityMatrix
+	                     -
+	                     ((householderVector at: 1) * v tensorProduct: v).
+	^ Array with: householderVector with: householderMatrix .
+]
+
 { #category : #private }
 PMQRDecomposition >> initialQMatrix [
 

From b27061309192c7b4a95fa5e92045cbcafb3bbf22 Mon Sep 17 00:00:00 2001
From: hemalvarambhia <h.n.varambhia@gmail.com>
Date: Sun, 11 Sep 2022 13:51:33 +0100
Subject: [PATCH 09/14] Made similar code even more similar.

---
 src/Math-Matrix/PMQRDecomposition.class.st | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/Math-Matrix/PMQRDecomposition.class.st b/src/Math-Matrix/PMQRDecomposition.class.st
index b2aeced3..b0ab6118 100644
--- a/src/Math-Matrix/PMQRDecomposition.class.st
+++ b/src/Math-Matrix/PMQRDecomposition.class.st
@@ -79,13 +79,13 @@ PMQRDecomposition >> decomposeWithPivot [
 	rank := 0.
 	identityMatrix := PMSymmetricMatrix identity: colSize.
 	[ 
-	| householderMatrix |
+	| householderMatrix columnVectorFromRMatrix |
 	rank := rank + 1.
 	pivot at: rank put: mx.
 	r swapColumn: rank withColumn: mx.
 	vectorOfNormSquareds swap: rank with: mx.
-	householderVector := (r columnVectorAt: rank size: colSize)
-		                     householder.
+	columnVectorFromRMatrix := r columnVectorAt: rank size: colSize.
+	householderVector := columnVectorFromRMatrix householder.
 	v := (PMVector zeros: rank - 1) , (householderVector at: 2).
 	householderMatrix := identityMatrix
 	                     -

From 5fb1e1bb577ea7130fe1b518a0c5b444893a9c52 Mon Sep 17 00:00:00 2001
From: hemalvarambhia <h.n.varambhia@gmail.com>
Date: Sun, 11 Sep 2022 13:53:21 +0100
Subject: [PATCH 10/14] Reduced the scope of the identity matrix to the code
 block.

---
 src/Math-Matrix/PMQRDecomposition.class.st | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/Math-Matrix/PMQRDecomposition.class.st b/src/Math-Matrix/PMQRDecomposition.class.st
index b0ab6118..ec18ff20 100644
--- a/src/Math-Matrix/PMQRDecomposition.class.st
+++ b/src/Math-Matrix/PMQRDecomposition.class.st
@@ -71,15 +71,14 @@ https://en.wikipedia.org/wiki/QR_decomposition#Using_Householder_reflections
 { #category : #arithmetic }
 PMQRDecomposition >> decomposeWithPivot [
 
-	| identityMatrix householderVector i v vectorOfNormSquareds rank mx pivot matrixOfMinor |
+	| householderVector i v vectorOfNormSquareds rank mx pivot matrixOfMinor |
 	vectorOfNormSquareds := matrixToDecompose columnsCollect: [ 
 		                        :columnVector | columnVector * columnVector ].
 	mx := vectorOfNormSquareds indexOf: vectorOfNormSquareds max.
 	pivot := Array new: vectorOfNormSquareds size.
 	rank := 0.
-	identityMatrix := PMSymmetricMatrix identity: colSize.
 	[ 
-	| householderMatrix columnVectorFromRMatrix |
+	| householderMatrix columnVectorFromRMatrix identityMatrix |
 	rank := rank + 1.
 	pivot at: rank put: mx.
 	r swapColumn: rank withColumn: mx.
@@ -87,6 +86,7 @@ PMQRDecomposition >> decomposeWithPivot [
 	columnVectorFromRMatrix := r columnVectorAt: rank size: colSize.
 	householderVector := columnVectorFromRMatrix householder.
 	v := (PMVector zeros: rank - 1) , (householderVector at: 2).
+	identityMatrix := PMSymmetricMatrix identity: colSize.
 	householderMatrix := identityMatrix
 	                     -
 	                     ((householderVector at: 1) * v tensorProduct: v).

From 9baa7baafb2af6462d47b6fc22d763eeff24def4 Mon Sep 17 00:00:00 2001
From: hemalvarambhia <h.n.varambhia@gmail.com>
Date: Sun, 11 Sep 2022 13:58:54 +0100
Subject: [PATCH 11/14] We now use the new method and have reduced the scope of
 a temporary variable.

---
 src/Math-Matrix/PMQRDecomposition.class.st | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/src/Math-Matrix/PMQRDecomposition.class.st b/src/Math-Matrix/PMQRDecomposition.class.st
index ec18ff20..13281664 100644
--- a/src/Math-Matrix/PMQRDecomposition.class.st
+++ b/src/Math-Matrix/PMQRDecomposition.class.st
@@ -71,25 +71,25 @@ https://en.wikipedia.org/wiki/QR_decomposition#Using_Householder_reflections
 { #category : #arithmetic }
 PMQRDecomposition >> decomposeWithPivot [
 
-	| householderVector i v vectorOfNormSquareds rank mx pivot matrixOfMinor |
+	| i v vectorOfNormSquareds rank mx pivot matrixOfMinor |
 	vectorOfNormSquareds := matrixToDecompose columnsCollect: [ 
 		                        :columnVector | columnVector * columnVector ].
 	mx := vectorOfNormSquareds indexOf: vectorOfNormSquareds max.
 	pivot := Array new: vectorOfNormSquareds size.
 	rank := 0.
 	[ 
-	| householderMatrix columnVectorFromRMatrix identityMatrix |
+	| householderReflection householderMatrix householderVector columnVectorFromRMatrix |
 	rank := rank + 1.
 	pivot at: rank put: mx.
 	r swapColumn: rank withColumn: mx.
 	vectorOfNormSquareds swap: rank with: mx.
 	columnVectorFromRMatrix := r columnVectorAt: rank size: colSize.
-	householderVector := columnVectorFromRMatrix householder.
-	v := (PMVector zeros: rank - 1) , (householderVector at: 2).
-	identityMatrix := PMSymmetricMatrix identity: colSize.
-	householderMatrix := identityMatrix
-	                     -
-	                     ((householderVector at: 1) * v tensorProduct: v).
+	householderReflection := self
+		                         householderReflectionOf:
+		                         columnVectorFromRMatrix
+		                         atColumnNumber: rank.
+	householderVector := householderReflection at: 1.
+	householderMatrix := householderReflection at: 2.
 	q := q * householderMatrix.
 	matrixOfMinor := r minor: rank - 1 and: rank - 1.
 	matrixOfMinor := matrixOfMinor

From c34d9cce651e26a7fae728984c9c0d10a4701112 Mon Sep 17 00:00:00 2001
From: hemalvarambhia <h.n.varambhia@gmail.com>
Date: Sun, 11 Sep 2022 14:04:02 +0100
Subject: [PATCH 12/14] Removed an unused local variable.

---
 src/Math-Matrix/PMQRDecomposition.class.st | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Math-Matrix/PMQRDecomposition.class.st b/src/Math-Matrix/PMQRDecomposition.class.st
index 13281664..e2da73d2 100644
--- a/src/Math-Matrix/PMQRDecomposition.class.st
+++ b/src/Math-Matrix/PMQRDecomposition.class.st
@@ -71,7 +71,7 @@ https://en.wikipedia.org/wiki/QR_decomposition#Using_Householder_reflections
 { #category : #arithmetic }
 PMQRDecomposition >> decomposeWithPivot [
 
-	| i v vectorOfNormSquareds rank mx pivot matrixOfMinor |
+	| i vectorOfNormSquareds rank mx pivot matrixOfMinor |
 	vectorOfNormSquareds := matrixToDecompose columnsCollect: [ 
 		                        :columnVector | columnVector * columnVector ].
 	mx := vectorOfNormSquareds indexOf: vectorOfNormSquareds max.

From 009e6778e2b37b375df8cb433d0269946d219f82 Mon Sep 17 00:00:00 2001
From: hemalvarambhia <h.n.varambhia@gmail.com>
Date: Sun, 11 Sep 2022 14:42:30 +0100
Subject: [PATCH 13/14] Reduced the scope of a temporary variable and made
 similar code (variable listing) even more similar.

---
 src/Math-Matrix/PMQRDecomposition.class.st | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/Math-Matrix/PMQRDecomposition.class.st b/src/Math-Matrix/PMQRDecomposition.class.st
index e2da73d2..237c4c3c 100644
--- a/src/Math-Matrix/PMQRDecomposition.class.st
+++ b/src/Math-Matrix/PMQRDecomposition.class.st
@@ -29,9 +29,9 @@ that describes the mechanics:
 https://en.wikipedia.org/wiki/QR_decomposition#Using_Householder_reflections
 "
 
-	| i matrixOfMinor householderReflection |
+	| i matrixOfMinor |
 	1 to: self numberOfColumns do: [ :col | 
-		| householderVector householderMatrix columnVectorFromRMatrix |
+		| householderReflection householderMatrix householderVector columnVectorFromRMatrix |
 		columnVectorFromRMatrix := r columnVectorAt: col size: colSize.
 		householderReflection := self
 			                         householderReflectionOf:

From 04cc08a5cf8816b6376b23acbf5fe55a2ea80bff Mon Sep 17 00:00:00 2001
From: hemalvarambhia <h.n.varambhia@gmail.com>
Date: Sun, 25 Sep 2022 10:19:34 +0100
Subject: [PATCH 14/14] Improved the name of a local variable.

---
 src/Math-Matrix/PMQRDecomposition.class.st | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/src/Math-Matrix/PMQRDecomposition.class.st b/src/Math-Matrix/PMQRDecomposition.class.st
index 237c4c3c..f5213976 100644
--- a/src/Math-Matrix/PMQRDecomposition.class.st
+++ b/src/Math-Matrix/PMQRDecomposition.class.st
@@ -71,18 +71,18 @@ https://en.wikipedia.org/wiki/QR_decomposition#Using_Householder_reflections
 { #category : #arithmetic }
 PMQRDecomposition >> decomposeWithPivot [
 
-	| i vectorOfNormSquareds rank mx pivot matrixOfMinor |
+	| i vectorOfNormSquareds rank positionOfMaximum pivot matrixOfMinor |
 	vectorOfNormSquareds := matrixToDecompose columnsCollect: [ 
 		                        :columnVector | columnVector * columnVector ].
-	mx := vectorOfNormSquareds indexOf: vectorOfNormSquareds max.
+	positionOfMaximum := vectorOfNormSquareds indexOf: vectorOfNormSquareds max.
 	pivot := Array new: vectorOfNormSquareds size.
 	rank := 0.
 	[ 
 	| householderReflection householderMatrix householderVector columnVectorFromRMatrix |
 	rank := rank + 1.
-	pivot at: rank put: mx.
-	r swapColumn: rank withColumn: mx.
-	vectorOfNormSquareds swap: rank with: mx.
+	pivot at: rank put: positionOfMaximum.
+	r swapColumn: rank withColumn: positionOfMaximum.
+	vectorOfNormSquareds swap: rank with: positionOfMaximum.
 	columnVectorFromRMatrix := r columnVectorAt: rank size: colSize.
 	householderReflection := self
 		                         householderReflectionOf:
@@ -115,16 +115,16 @@ PMQRDecomposition >> decomposeWithPivot [
 			- (r rowAt: rank columnAt: ind) squared ].
 	rank < vectorOfNormSquareds size
 		ifTrue: [ 
-			mx := (vectorOfNormSquareds
+			positionOfMaximum := (vectorOfNormSquareds
 				       copyFrom: rank + 1
 				       to: vectorOfNormSquareds size) max.
-			(mx closeTo: 0) ifTrue: [ mx := 0 ].
-			mx := mx > 0
+			(positionOfMaximum closeTo: 0) ifTrue: [ positionOfMaximum := 0 ].
+			positionOfMaximum := positionOfMaximum > 0
 				      ifTrue: [ 
-				      vectorOfNormSquareds indexOf: mx startingAt: rank + 1 ]
+				      vectorOfNormSquareds indexOf: positionOfMaximum startingAt: rank + 1 ]
 				      ifFalse: [ 0 ] ]
-		ifFalse: [ mx := 0 ].
-	mx > 0 ] whileTrue.
+		ifFalse: [ positionOfMaximum := 0 ].
+	positionOfMaximum > 0 ] whileTrue.
 	i := 0.
 	[ (r rowAt: colSize) isZero ] whileTrue: [ 
 		i := i + 1.