_ad_init_zero for EnsembleFunction

Author: JHopeCollins

firedrake/adjoint_utils/ensemble_function.py

@@ -55,6 +55,13 @@ def _ad_dot(self, other, options=None):
     def _ad_convert_riesz(self, value, options=None):
         raise NotImplementedError
 
+    def _ad_init_zero(self, dual=False):
+        from firedrake import EnsembleFunction, EnsembleCofunction
+        if dual:
+            return EnsembleCofunction(self.function_space().dual())
+        else:
+            return EnsembleFunction(self.function_space())
+
     def _ad_create_checkpoint(self):
         if disk_checkpointing():
             raise NotImplementedError(