diff --git a/+quantity/Discrete.m b/+quantity/Discrete.m
index 826e34ac121eb41bc9c3a6fc247bc78306ca7548..ba6d07c6cfb42356727738c8de3838c2d2d8aa50 100644
--- a/+quantity/Discrete.m
+++ b/+quantity/Discrete.m
@@ -1869,6 +1869,28 @@ classdef  (InferiorClasses = {?quantity.Symbolic}) Discrete ...
 			end
 		end % isdiag()
 		
+		function result = isnan(obj, anyNan)
+			%  isnan  True for Not-a-Number.
+			%     isnan(X) returns an array that contains true's where
+			%     the elements of X are NaN's and false's where they are not.
+			%
+			%     isnan(X, true) returns the same as any(isnan(X), 'all')
+			
+			arguments
+				obj
+				anyNan = false;
+			end
+			
+			if anyNan
+				result = any(isnan(obj.on()), 'all');
+			else
+				result = true(size(obj));
+				for it = 1 : numel(obj)
+					result(it) = any(isnan(obj(it).on()), 'all');
+				end
+			end	
+		end % isnan()
+		
 		function P = ztzTimes(a, b)
 			
 			assert(size(a,2) == size(b,1))
diff --git a/+unittests/+quantity/testDomain.m b/+unittests/+quantity/testDomain.m
index b92c4ff62c07df5763e985e2914f9733bd32f9aa..11ee1963e5db1e7dbf3a4d522e3f796a5a34a554 100644
--- a/+unittests/+quantity/testDomain.m
+++ b/+unittests/+quantity/testDomain.m
@@ -20,13 +20,13 @@ end
 
 function testParser(testCase)
 
-profile on
+%profile on
 d = quantity.Domain.parser('blub', 1, 'grid', 1:3, 'gridName', 'test');
 a = quantity.Domain.parser('domain', d);
 b = quantity.Domain.parser('blabla', 0, 'domain', a);
 b = quantity.Domain.parser('blabla', 0, 'domain', a, 'blub', 'a');
-profile off
-profile viewer
+%profile off
+%profile viewer
 
 
 testCase.verifyEqual(d, a);