Adjfloat block variables to print saved values.

pyadjoint/adjfloat.py

@@ -123,6 +123,10 @@ def _ad_to_list(value):
     def _ad_copy(self):
         return self
 
+    @property
+    def _ad_str(self):
+        """Return the string of the taped value of this variable."""
+        return str(self.block_variable.saved_output)
 
 _min = min
 _max = max

pyadjoint/block_variable.py

@@ -68,7 +68,7 @@ def will_add_as_output(self):
         self.save_output(overwrite=overwrite)
 
     def __str__(self):
-        return str(self.output)
+        return str(self.output._ad_str)
 
     @property
     def checkpoint(self):

pyadjoint/overloaded_type.py

@@ -308,6 +308,18 @@ def _ad_dim(self):
         """
         raise NotImplementedError
 
+    def _ad_str(self):
+        """Return the string representation of the block variable.
+
+        For simple scalar types this might be the string representation of the
+        stored value. For more complex objects it is likely to be based on a
+        name attached to this instance.
+
+        Returns:
+            str: A human readable serialisation of this variable.
+        """
+        return str(self)
+
 
 class FloatingType(OverloadedType):
     def __init__(self, *args, **kwargs):