Make the progress bar print optional.

pyadjoint/checkpointing.py

@@ -214,8 +214,7 @@ def evaluate_adj(self, last_block, markings):
         if self.mode not in (Mode.EVALUATED, Mode.FINISHED_RECORDING):
             raise CheckpointError("Evaluate Functional before calling gradient.")
 
-        with self.tape.progress_bar("Evaluating Adjoint",
-                                    max=self.timesteps) as bar:
+        with self.tape.progress_bar("Evaluating Adjoint", max=self.timesteps) as bar:
             if self.adjoint_evaluated:
                 reverse_iterator = iter(self.reverse_schedule)
             while not isinstance(self._current_action, EndReverse):
@@ -257,10 +256,8 @@ def process_operation(self, cp_action, bar, **kwargs):
     def _(self, cp_action, bar, functional=None, **kwargs):
         for step in cp_action:
             if self.mode == Mode.RECOMPUTE:
-                try:
+                if bar:
                     bar.next()
-                except AttributeError:
-                    pass
             # Get the blocks of the current step.
             current_step = self.tape.timesteps[step]
             for block in current_step:
@@ -293,10 +290,8 @@ def _(self, cp_action, bar, functional=None, **kwargs):
     @process_operation.register(Reverse)
     def _(self, cp_action, bar, markings, functional=None, **kwargs):
         for step in cp_action:
-            try:
+            if bar:
                 bar.next()
-            except AttributeError:
-                pass
             # Get the blocks of the current step.
             current_step = self.tape.timesteps[step]
             for block in reversed(current_step):

pyadjoint/tape.py

@@ -703,7 +703,7 @@ def __init__(self, *args, **kwargs):
     def __enter__(self):
         pass
 
-    def __exit__(self):
+    def __exit__(self, *args, **kwargs):
         pass
 
     def iter(self, iterator):