Add TransposeOperator, fix plotting

src/operators/operator.py

@@ -250,7 +250,7 @@ class Operator(metaclass=NiftyMeta):
         if not is_operator(self):
             return NotImplemented
         if not isinstance(self.target, MultiDomain):
-            raise TypeError("Only Operators with a MultiDomain as target get be subscipted.")
+            raise TypeError("Only Operators with a MultiDomain as target can be subscripted.")
         return ducktape(None, self, key) @ self
 
     def apply(self, x):
@@ -314,6 +314,22 @@ class Operator(metaclass=NiftyMeta):
             dom = self.domain if is_fieldlike(self) else self.target
             return DomainChangerAndReshaper(dom, newdom)(self)
 
+    def transpose(self, indices):
+        """Transposes a Field.
+
+        Parameters
+        ----------
+        indices : tuple
+            Must be a tuple or list which contains a permutation of
+            [0,1,..,N-1] where N is the number of domains in the target of the
+            Operator (or the Field).
+        """
+        from .transpose_operator import TransposeOperator
+        from ..sugar import is_fieldlike
+
+        dom = self.domain if is_fieldlike(self) else self.target
+        return TransposeOperator(dom, indices)(self)
+
     def __repr__(self):
         return self.__class__.__name__