diff -r 33d4825d883d -r 5dee87e2266e Matrix.st
--- a/Matrix.st	Tue Aug 20 15:25:21 2019 +0200
+++ b/Matrix.st	Tue Aug 20 15:30:29 2019 +0200
@@ -1,3 +1,5 @@
+"{ Encoding: utf8 }"
+
 "{ Package: 'stx:libbasic2' }"
 
 "{ NameSpace: Smalltalk }"
@@ -375,7 +377,9 @@
 
     | result |
 
-    dimensions = aMatrix dimensions ifFalse: [ IncompatibleMatrixError signal ].
+    dimensions = aMatrix dimensions ifFalse: [ 
+        IncompatibleMatrixError raiseRequestWith:aMatrix errorString:'argument matrix has different dimensions'
+    ].
 
     result := (self class new:(self basicSize)) dimensions:dimensions.
 
@@ -390,7 +394,9 @@
 
     | result |
 
-    dimensions = aMatrix dimensions ifFalse: [ IncompatibleMatrixError signal ].
+    dimensions = aMatrix dimensions ifFalse: [
+        IncompatibleMatrixError raiseRequestWith:aMatrix errorString:'argument matrix has different dimensions'
+    ].
 
     result := (self class new:(self basicSize)) dimensions:dimensions.
 
@@ -403,7 +409,7 @@
 !Matrix methodsFor:'matrix operations'!
 
 determinant
-    MatrixError signal: 'Matrix must be square'
+    IncompatibleMatrixError raiseRequestWith:self errorString: 'Matrix must be square'
 ! !
 
 !Matrix methodsFor:'private'!