diff --git a/docs/source/objectives.rst b/docs/source/objectives.rst
index da8e28a..58e89f9 100644
--- a/docs/source/objectives.rst
+++ b/docs/source/objectives.rst
@@ -21,7 +21,7 @@ We can construct an objective to maximize some output with
 
     objective = Objective(name="some_output", target="max") # or "min"
 
-Given some data, the ``Objective`` object will try to model the quantity ``y1`` and find the corresponding inputs that maximize it.
+Given some data, the ``Objective`` object will try to model the quantity ``some_output`` and find the corresponding inputs that maximize it.
 We can also apply a transform to the value to make it more Gaussian when we fit to it.
 This is especially useful when the quantity tends to be non-Gaussian, like with a beam flux.
 
@@ -29,9 +29,9 @@ This is especially useful when the quantity tends to be non-Gaussian, like with
 
     from blop import Objective
 
-    objective = Objective(name="some_output", target="max", transform="log")
+    objective_with_log_transform = Objective(name="some_output", target="max", transform="log")
 
-    objective = Objective(name="some_output", target="max", transform="arctanh")
+    objective_with_arctanh_transform = Objective(name="some_output", target="max", transform="arctanh")
 
 
 .. code-block:: python
@@ -62,13 +62,13 @@ This is useful in optimization problems like
 .. code-block:: python
 
     # ensure the color is approximately green
-    objective = Objective(name="peak_wavelength", target=(520, 530), units="nm")
+    color_bjective = Objective(name="peak_wavelength", target=(520, 530), units="nm")
 
     # ensure the beam is smaller than 10 microns
-    objective = Objective(name="beam_width", target=(-np.inf, 10), units="um", transform="log")
+    width_objective = Objective(name="beam_width", target=(-np.inf, 10), units="um", transform="log")
 
     # ensure our flux is at least some value
-    objective = Objective(name="beam_flux", target=(1.0, np.inf), transform="log")
+    flux_objective = Objective(name="beam_flux", target=(1.0, np.inf), transform="log")
 
 
 
diff --git a/src/blop/agent.py b/src/blop/agent.py
index 231ab23..0a170cd 100644
--- a/src/blop/agent.py
+++ b/src/blop/agent.py
@@ -198,7 +198,7 @@ def sample(self, n: int = DEFAULT_MAX_SAMPLES, method: str = "quasi-random") ->
         else:
             raise ValueError("'method' argument must be one of ['quasi-random', 'random', 'grid'].")
 
-        return self.dofs.untransform(X)
+        return self.dofs.subset(active=True).untransform(X)
 
     def ask(self, acq_func_identifier="qei", n=1, route=True, sequential=True, upsample=1, **acq_func_kwargs):
         """Ask the agent for the best point to sample, given an acquisition function.
@@ -260,7 +260,7 @@ def ask(self, acq_func_identifier="qei", n=1, route=True, sequential=True, upsam
 
             # this includes both RO and non-RO DOFs.
             # and is in the transformed model space
-            candidates = self.dofs.untransform(candidates).numpy()
+            candidates = self.dofs.subset(active=True).untransform(candidates).numpy()
 
         p = self.posterior(candidates) if hasattr(self, "model") else None
 
@@ -586,10 +586,10 @@ def scalarized_fitnesses(self, weights="default", constrained=True):
         return torch.where(c, f, -np.inf)
 
     def argmax_best_f(self, weights="default"):
-        return self.scalarized_fitnesses(weights=weights, constrained=True).argmax()
+        return int(self.scalarized_fitnesses(weights=weights, constrained=True).argmax())
 
     def best_f(self, weights="default"):
-        return self.scalarized_fitnesses(weights=weights, constrained=True).max()
+        return float(self.scalarized_fitnesses(weights=weights, constrained=True).max())
 
     @property
     def pareto_front_mask(self):
@@ -741,7 +741,7 @@ def _sample_domain(self):
         Read-only DOFs are set to exactly their last known value.
         Discrete DOFs are relaxed to some continuous domain.
         """
-        return self.dofs.transform(self.dofs.subset(active=True).search_domain.T)
+        return self.dofs.subset(active=True).transform(self.dofs.subset(active=True).search_domain.T)
 
     @property
     def _model_input_transform(self):
@@ -802,7 +802,7 @@ def _set_hypers(self, hypers):
         self.validity_constraint.load_state_dict(hypers["validity_constraint"])
 
     def constraint(self, x):
-        x = self.dofs.transform(x)
+        x = self.dofs.subset(active=True).transform(x)
 
         p = torch.ones(x.shape[:-1])
         for obj in self.active_objs:
@@ -922,12 +922,12 @@ def train_targets(self, index=None, **subset_kwargs):
     @property
     def best(self):
         """Returns all data for the best point."""
-        return self.table.loc[int(self.argmax_best_f())]
+        return self.table.loc[self.argmax_best_f()]
 
     @property
     def best_inputs(self):
         """Returns the value of each DOF at the best point."""
-        return self.table.loc[int(self.argmax_best_f()), self.dofs.names].to_dict()
+        return self.table.loc[self.argmax_best_f(), self.dofs.names].to_dict()
 
     def go_to(self, **positions):
         """Set all settable DOFs to a given position. DOF/value pairs should be supplied as kwargs, e.g. as
diff --git a/src/blop/dofs.py b/src/blop/dofs.py
index 8ecce32..5d3b90c 100644
--- a/src/blop/dofs.py
+++ b/src/blop/dofs.py
@@ -53,10 +53,11 @@ def _validate_continuous_dof_domains(search_domain, trust_domain, domain, read_o
     search_domain \\subseteq trust_domain \\subseteq domain
     """
     if not read_only:
+        if len(search_domain) != 2:
+            raise ValueError(f"Bad search domain {search_domain}. The search domain must have length 2.")
         try:
             search_domain = tuple((float(search_domain[0]), float(search_domain[1])))
-            assert len(search_domain) == 2
-        except:  # noqa
+        except TypeError:
             raise ValueError("If type='continuous', then 'search_domain' must be a tuple of two numbers.")
 
         if search_domain[0] >= search_domain[1]:
@@ -72,7 +73,7 @@ def _validate_continuous_dof_domains(search_domain, trust_domain, domain, read_o
 
     if (trust_domain is not None) and (domain is not None):
         if (trust_domain[0] < domain[0]) or (trust_domain[1] > domain[1]):
-            raise ValueError(f"The trust domain {trust_domain} must be a subset of the trust domain {domain}.")
+            raise ValueError(f"The trust domain {trust_domain} must be a subset of the domain {domain}.")
 
 
 def _validate_discrete_dof_domains(search_domain, trust_domain):
@@ -374,21 +375,20 @@ def transform(self, X):
         """
         Transform X to the transformed unit hypercube.
         """
-
-        if X.shape[-1] != len(self.subset(active=True)):
-            raise ValueError()
+        if X.shape[-1] != len(self):
+            raise ValueError(f"Cannot transform points with shape {X.shape} using DOFs with dimension {len(self)}.")
 
         if not isinstance(X, torch.Tensor):
             X = torch.tensor(X, dtype=torch.double)
 
-        return torch.cat([dof._transform(X[..., i]).unsqueeze(-1) for i, dof in enumerate(self.subset(active=True))], dim=-1)
+        return torch.cat([dof._transform(X[..., i]).unsqueeze(-1) for i, dof in enumerate(self.dofs)], dim=-1)
 
     def untransform(self, X):
         """
         Transform the transformed unit hypercube to the search domain.
         """
-        if X.shape[-1] != len(self.subset(active=True)):
-            raise ValueError()
+        if X.shape[-1] != len(self):
+            raise ValueError(f"Cannot untransform points with shape {X.shape} using DOFs with dimension {len(self)}.")
 
         if not isinstance(X, torch.Tensor):
             X = torch.tensor(X, dtype=torch.double)
diff --git a/src/blop/objectives.py b/src/blop/objectives.py
index 10e4784..f99e22b 100644
--- a/src/blop/objectives.py
+++ b/src/blop/objectives.py
@@ -389,7 +389,7 @@ def transform(self, Y):
         Transform the experiment space to the model space.
         """
         if Y.shape[-1] != len(self):
-            raise ValueError()
+            raise ValueError(f"Cannot transform points with shape {Y.shape} using DOFs with dimension {len(self)}.")
 
         if not isinstance(Y, torch.Tensor):
             Y = torch.tensor(Y, dtype=torch.double)
@@ -401,7 +401,7 @@ def untransform(self, Y):
         Transform the model space to the experiment space.
         """
         if Y.shape[-1] != len(self):
-            raise ValueError()
+            raise ValueError(f"Cannot untransform points with shape {Y.shape} using DOFs with dimension {len(self)}.")
 
         if not isinstance(Y, torch.Tensor):
             Y = torch.tensor(Y, dtype=torch.double)
diff --git a/src/blop/plotting.py b/src/blop/plotting.py
index 551f80b..2f69d9d 100644
--- a/src/blop/plotting.py
+++ b/src/blop/plotting.py
@@ -155,7 +155,7 @@ def _plot_objs_many_dofs(agent, axes=(0, 1), shading="nearest", cmap=DEFAULT_COL
     test_x = test_inputs[..., 0, axes[0]].detach().squeeze().numpy()
     test_y = test_inputs[..., 0, axes[1]].detach().squeeze().numpy()
 
-    model_inputs = agent.dofs.transform(test_inputs)
+    model_inputs = agent.dofs.subset(active=True).transform(test_inputs)
 
     for obj_index, obj in enumerate(agent.objectives):
         targets = agent.train_targets(obj.name).squeeze(-1).numpy()
diff --git a/src/blop/tests/conftest.py b/src/blop/tests/conftest.py
index 6506f53..9c81da8 100644
--- a/src/blop/tests/conftest.py
+++ b/src/blop/tests/conftest.py
@@ -107,7 +107,7 @@ def digestion(db, uid):
 @pytest.fixture(scope="function")
 def constrained_agent(db):
     """
-    https://en.wikipedia.org/wiki/Test_functions_for_optimization
+    Chankong and Haimes function from https://en.wikipedia.org/wiki/Test_functions_for_optimization
     """
 
     def digestion(db, uid):