added hash function to quantity.Discrete and misc

+misc/getDimensions.m

@@ -5,7 +5,7 @@ arguments
 	names cell;
 	dim = 1;
 end
-sizes = [];
+sizes = 0;
 for k = 1:length(names)
 	if isfield(optArg, names{k})
 		sizes(k) = size(optArg.(names{k}), dim);

+misc/hash.m

+function h = hash(data)
+%HASH compute the hash for some data
+%	h = hash(DATA) computes the SHA-1 hash for DATA
+
+	B = getByteStreamFromArray(data);
+	Engine = java.security.MessageDigest.getInstance('SHA-1');
+	Engine.update(B);
+
+	h = reshape( dec2hex(typecast(Engine.digest(), 'uint8')), 1, []);
+end
+

+quantity/Discrete.m

@@ -22,7 +22,7 @@ classdef  (InferiorClasses = {?quantity.Symbolic}) Discrete ...
 	end
 	
 	properties ( Dependent )
-		
+				
 		% Name of the domains that generate the grid.
 		gridName {mustBe.unique};
 		
@@ -239,6 +239,22 @@ classdef  (InferiorClasses = {?quantity.Symbolic}) Discrete ...
 	end
 	
 	methods (Access = public)
+		
+		function h = hash(obj)
+			%HASH create a SHA-1 hash value for this object
+			% h = hash(obj) will copmute the SHA-1 hash value based on the
+			% data "valueDiscrete", "domain.name", "domain.grid",
+			% "obj.name"
+			% The hash value can be used to get a "short" identifier for
+			% this object.
+			
+			% create a huge array of all relevant quantity data
+			data = {[ obj.valueDiscrete ], obj(1).domain.name, ...
+				    obj(1).domain.grid, obj(1).name};
+			h = misc.hash(data);
+			
+		end
+		
 		function d = compositionDomain(obj, domainName)
 			
 			assert(isscalar(obj));

+unittests/+quantity/testDiscrete.m

@@ -13,6 +13,19 @@ testCase.TestData.sym.t = t;
 testCase.TestData.sym.sy = sy;
 end
 
+function testHashData(testCase)
+
+	spatialDomain = quantity.Domain("z", linspace(0, 1, 101));
+	L1 = quantity.Symbolic(diag([2, -3]), ...
+					'domain', spatialDomain, 'name', 'Lambda');
+
+	L2 = quantity.Symbolic(diag([1, -1]), ...
+					'domain', spatialDomain, 'name', 'Lambda');
+	
+	testCase.verifyNotEqual(L1.hash, L2.hash);
+				
+end
+
 function testIsdiag(tc)
 z = quantity.Domain("z", linspace(0, 1, 11));