--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/m-toolbox/classes/@unit/eq.m	Wed Nov 23 19:22:13 2011 +0100
@@ -0,0 +1,91 @@
+% EQ overloads the == operator for ltpda unit objects.
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% DESCRIPTION: EQ overloads the == operator for ltpda unit objects.
+%
+%              Two units are considered equal if each has the same unit
+%              components with the same exponents and prefixes. The order
+%              of the units doesn't matter.
+%
+% CALL:        result = eq(u1,u2)
+%
+% INPUTS:      u1, u2     - Input objects
+%
+% OUTPUTS:     If the two objects are considered equal, result == true,
+%              otherwise, result == false.
+%
+% VERSION:     $Id: eq.m,v 1.14 2011/02/18 16:48:55 ingo Exp $
+%
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+function result = eq(obj1, obj2, varargin)
+  
+  import utils.const.*
+  
+  % Check class
+  if ~strcmp(class(obj1), class(obj2))
+    utils.helper.msg(msg.PROC1, 'NOT EQUAL: The objects are not from the same class. [%s] <-> [%s]', class(obj1), class(obj2));
+    result = false;
+    return
+  end
+  
+  % Check length of obj1 and obj2
+  if numel(obj1) ~= numel(obj2)
+    utils.helper.msg(msg.PROC1, 'NOT EQUAL: The size of the %s-object''s. [%d] <-> [%d]', class(obj1), numel(obj1), numel(obj2));
+    result = false;
+    return
+  end
+  
+  for objNo = 1:numel(obj1)
+    
+    % compare these two units
+    result = compare_units(obj1(objNo),obj2(objNo));
+    
+    % If they are not equal, we simplify and check again
+    % - simplify() is expensive, so only do if necessary
+    if ~result
+      % and make sure we get copies so we don't modify the user's inputs
+      c1 = obj1(objNo).simplify();
+      c2 = obj2(objNo).simplify();      
+      result = compare_units(c1,c2);
+    end
+    
+    if ~result
+      return
+    end
+    
+  end
+  
+end
+
+
+function result = compare_units(u1,u2)
+  
+  % simplify the input objects
+  matches = false(size(u1.strs));
+  
+  % same length?
+  if numel(u1.strs) ~= numel(u2.strs)
+    result = false;
+    return
+  end
+  
+  % Check all match
+  for oo=1:numel(u1.strs)
+    for ii=1:numel(u2.strs)
+      % Check that the strings and the values are the same
+      if strcmp(u1.strs{oo}, u2.strs{ii}) && u1.vals(oo) == u2.vals(ii)
+        % Check that the exponent are the same
+        % REMARK: It might be that there is a rounding problem. But then
+        %         For example: 1/3 - ( 1 - 2/3 ) ~= 0
+        %         In this example is the error equal the smalles error of (1/3)
+        if u1.exps(oo) == u2.exps(ii) || abs(u1.exps(oo) - u2.exps(ii)) == eps(u1.exps(oo))
+          matches(oo) = true;
+        end
+      end
+    end
+  end
+  
+  result = all(matches);
+  
+end