add identity matrix instance creation for PMMatrix

Author: rakki-18

src/Math-Matrix/PMMatrix.class.st

@@ -67,6 +67,11 @@ a tr.
 "15"
 ]
 
+{ #category : #'instance creation' }
+PMMatrix class >> identity: anInteger [ 
+  ^ PMSymmetricMatrix identity: anInteger 
+]
+
 { #category : #'instance creation' }
 PMMatrix class >> join: anArrayOfMatrices [
 		"Inverse of the split operation."

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

@@ -197,6 +197,20 @@ PMMatrixTest >> testFlattenRows [
 	self assert: m flattenRows equals: #(1 2 3 4 5 6 7 8 9) asPMVector
 ]
 
+{ #category : #tests }
+PMMatrixTest >> testIdentityMatrix [
+	|a a2|
+
+	a := PMMatrix zerosRows: 3 cols: 3.
+
+	a at: 1 at: 1 put: 1.
+	a at: 2 at: 2 put: 1.
+	a at: 3 at: 3 put: 1.
+
+	a2 := PMMatrix identity: 3.
+	self assert: a2 equals: a.
+]
+
 { #category : #tests }
 PMMatrixTest >> testIsRealOnComplexMatrix [
 	| matrix |

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

@@ -1,7 +1,7 @@
 Class {
 	#name : #PMSymmetricMatrixTest,
 	#superclass : #TestCase,
-	#category : 'Math-Tests-Matrix'
+	#category : #'Math-Tests-Matrix'
 }
 
 { #category : #tests }
@@ -38,6 +38,16 @@ PMSymmetricMatrixTest >> testEqual [
 	self assert: b ~= a
 ]
 
+{ #category : #tests }
+PMSymmetricMatrixTest >> testIdentityMatrix [
+	|a a1|
+
+	a := PMSymmetricMatrix identity: 3.
+	a1 := PMSymmetricMatrix rows: #(#(1 0 0) #(0 1 0) #(0 0 1)).
+
+	self assert: a equals: a1.
+]
+
 { #category : #tests }
 PMSymmetricMatrixTest >> testInversePureLUP [
 	| m i |