diff --git a/simulai/residuals/_pytorch_residuals.py b/simulai/residuals/_pytorch_residuals.py
index 5038f23..b6a38f3 100644
--- a/simulai/residuals/_pytorch_residuals.py
+++ b/simulai/residuals/_pytorch_residuals.py
@@ -72,7 +72,7 @@ def __init__(
         self.processing = processing
         self.periodic_bc_protected_key = "periodic"
 
-        self.protected_funcs = ["cos", "sin", "sqrt", "exp", "tanh"]
+        self.protected_funcs = ["cos", "sin", "sqrt", "exp", "tanh", "cosh", "sech", "sinh"]
         self.protected_operators = ["L", "Div", "Identity", "Kronecker"]
 
         self.protected_funcs_subs = self._construct_protected_functions()
@@ -186,9 +186,18 @@ def _construct_protected_functions(self):
         Returns:
             dict: A dictionary of function names and their corresponding function objects.
         """
-        protected_funcs = {
-            func: getattr(self.engine, func) for func in self.protected_funcs
-        }
+        protected_funcs = dict()
+
+        for func in self.protected_funcs:
+            try:
+                func_op = getattr(self.engine, func)
+            except:
+                try:
+                    func_op = getattr(self, func)
+                except:
+                    raise Exception(f"Operator {func} is not defined.")
+
+            protected_funcs[func] = func_op
 
         return protected_funcs
 
@@ -618,6 +627,25 @@ def inner(inputs):
 
         return jacobian(inner, inputs)
 
+    def sech(self, x):
+
+        cosh = getattr(self.engine, "cosh")
+
+        return 1/cosh(x)
+
+    def csch(self, x):
+
+        sinh = getattr(self.engine, "sinh")
+
+        return 1/sinh(x)
+
+    def coth(self, x):
+
+        cosh = getattr(self.engine, "cosh")
+        sinh = getattr(self.engine, "sinh")
+
+        return cosh(x)/sinh(x)
+
 
 def diff(feature: torch.Tensor, param: torch.Tensor) -> torch.Tensor:
     """Calculates the gradient of the given feature with respect to the given parameter.
diff --git a/tests/residuals/test_symbolicoperator.py b/tests/residuals/test_symbolicoperator.py
index 4023e4f..4a410d7 100644
--- a/tests/residuals/test_symbolicoperator.py
+++ b/tests/residuals/test_symbolicoperator.py
@@ -98,7 +98,7 @@ def model_operator():
         branch_network=branch_net,
         var_dim=n_outputs,
         rescale_factors=np.array([1]),
-        devices="gpu",
+        devices="cpu",
         model_id="flame_net",
     )
 
@@ -171,7 +171,7 @@ def test_symbolic_buitin_functions(self):
         assert all([isinstance(item, torch.Tensor) for item in residual(input_data)])
 
     def test_symbolic_operator_ode(self):
-        for token in ["sin", "cos", "sqrt", "tanh"]:
+        for token in ["sin", "cos", "sqrt", "tanh", "cosh", "sech", "coth", "sinh"]:
             f = f"D(u, t) - alpha*{token}(u)"
 
             input_labels = ["t"]