Fields can now be added to the "highest" one

Author: m.lohmann

odl/operator/operator.py

@@ -1071,7 +1071,6 @@ class OperatorSum(Operator):
 
     The sum is only well-defined for `Operator` instances where
     `Operator.range` is a `LinearSpace`.
-
     """
 
     def __init__(self, left, right, tmp_ran=None, tmp_dom=None):
@@ -1106,8 +1105,14 @@ def __init__(self, left, right, tmp_ran=None, tmp_dom=None):
         rn(3).element([ 2.,  4.,  6.])
         """
         if left.range != right.range:
-            raise OpTypeError('operator ranges {!r} and {!r} do not match'
-                              ''.format(left.range, right.range))
+            if isinstance(left.range, Field) and \
+                    isinstance(right.range, Field):
+                range = left.range + right.range
+            else:
+                raise OpTypeError('operator ranges {!r} and {!r} do not match'
+                                  ''.format(left.range, right.range))
+        else:
+            range = left.range
         if not isinstance(left.range, (LinearSpace, Field)):
             raise OpTypeError('`left.range` {!r} not a `LinearSpace` or '
                               '`Field` instance'.format(left.range))
@@ -1124,7 +1129,7 @@ def __init__(self, left, right, tmp_ran=None, tmp_dom=None):
                                 ''.format(tmp_dom, left.domain))
 
         super(OperatorSum, self).__init__(
-            left.domain, left.range,
+            left.domain, range,
             linear=left.is_linear and right.is_linear)
         self.__left = left
         self.__right = right

odl/set/sets.py

@@ -310,6 +310,25 @@ def field(self):
         """
         return self
 
+    def contains_set(self, other):
+        raise NotImplementedError('field {!r} does not have method '
+                                  '`contains_set`'.format(self))
+
+    def __add__(self, other):
+        if self.contains_set(other):
+            return self
+        elif other.contains_set(self):
+            return other
+        else:
+            raise ValueError('Fields {!r} and {!r} do not include '
+                             'each other'.format(self, other))
+
+    def __radd__(self, other):
+        if other == 0:
+            return self
+        else:
+            return self.__add__(other)
+
 
 class ComplexNumbers(Field):
 
@@ -428,10 +447,7 @@ def __hash__(self):
 
     def element(self, inp=None):
         """Return a real number from ``inp`` or from scratch."""
-        if inp is not None:
-            return float(inp)
-        else:
-            return 0.0
+        return float(getattr(inp, 'real', 0.0))
 
     @property
     def examples(self):