Allow empty stimulus

jaxley/integrate.py

@@ -41,8 +41,18 @@ def integrate(
 
     assert module.initialized, "Module is not initialized, run `.initialize()`."
 
-    i_current = module.currents.T if currents is None else currents.T
-    i_inds = module.current_inds.comp_index.to_numpy()
+    if module.currents is not None:
+        # At least one stimulus was inserted.
+        i_current = currents.T if currents is not None else module.currents.T
+        i_inds = module.current_inds.comp_index.to_numpy()
+    else:
+        # No stimulus was inserted.
+        i_current = jnp.asarray([[]]).astype("int")
+        i_inds = jnp.asarray([]).astype("int")
+        assert (
+            t_max is not None
+        ), "If no stimulus is inserted that you have to specify the simulation duration at `jx.integrate(..., t_max=)`."
+
     rec_inds = module.recordings.comp_index.to_numpy()
 
     # Shorten or pad stimulus depending on `t_max`.