Fix TriangulizedMat([])

gap-system · Mar 12, 2018 · 189635d · 189635d
1 parent c1fb98f
commit 189635d
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diff --git a/lib/matrix.gi b/lib/matrix.gi
@@ -2949,6 +2949,9 @@ local m;
   return m;
 end);
 
+InstallOtherMethod( TriangulizedMat, "for an empty list", [ IsList and IsEmpty ],
+mat -> []);
+
 #############################################################################
 ##
 #M  UpperSubdiagonal( <mat>, <pos> )

diff --git a/tst/testinstall/opers/TriangulizedMat.tst b/tst/testinstall/opers/TriangulizedMat.tst
@@ -0,0 +1,33 @@
+gap> START_TEST("TriangulizedMat.tst");
+
+#
+gap> a:=[];;
+gap> b:=TriangulizedMat(a);
+[  ]
+gap> a = [];
+true
+gap> IsIdenticalObj(a, b);
+false
+
+#
+gap> a:=[[42]];;
+gap> b:=TriangulizedMat(a);
+[ [ 1 ] ]
+gap> a = [[42]];
+true
+
+#
+gap> a:=[[Z(7)]];;
+gap> b:=TriangulizedMat(a);
+[ [ Z(7)^0 ] ]
+gap> a = [[Z(7)]];
+true
+
+#
+gap> TriangulizedMat([[1,2],[3,4]]);
+[ [ 1, 0 ], [ 0, 1 ] ]
+gap> TriangulizedMat([[1,2],[3,6]]);
+[ [ 1, 2 ], [ 0, 0 ] ]
+
+#
+gap> STOP_TEST("TriangulizedMat.tst", 1);