fix: use-after-free in socket pruner

Also the usual batch of improvements.
Differentiability is misbehaving, intriguingly.

src/blender_maxwell/node_trees/maxwell_sim_nodes/contracts/flow_kinds/lazy_func.py

@@ -325,8 +325,16 @@ class FuncFlow(pyd.BaseModel):
 		symbol_values: dict[sim_symbols.SimSymbol, spux.SympyExpr] = MappingProxyType(
 			{}
 		),
+		disallow_jax: bool = True,
 	) -> typ.Self:
-		"""Run the represented function with the best optimization available, given particular choices for all function arguments and for all unrealized symbols."""
+		"""Run the represented function with the best optimization available, given particular choices for all function arguments and for all unrealized symbols.
+
+		Parameters:
+			params: The parameter-tracking object from which function arguments will be computed.
+			symbol_values: Values for all `SimSymbol`s that are not yet realized in `params`.
+			disallow_jax: Don't use `self.func_jax` to evaluate, even if possible.
+				This is desirable when the overhead of `jax.jit()` is known in advance to exceed the performance benefits.
+		"""
 		if self.supports_jax:
 			return self.func_jax(
 				*params.scaled_func_args(symbol_values),

src/blender_maxwell/node_trees/maxwell_sim_nodes/nodes/base.py

@@ -374,19 +374,22 @@ class MaxwellSimNode(bpy.types.Node, bl_instance.BLInstance):
 		"""
 		node_tree = self.id_data
 		for direc in ['input', 'output']:
-			bl_sockets = self._bl_sockets(direc)
+			active_socket_nametype = {
+				bl_socket.name: bl_socket.socket_type
+				for bl_socket in self._bl_sockets(direc)
+			}
 			active_socket_defs = self.active_socket_defs(direc)
 
 			# Determine Sockets to Remove
 			## -> Name: If the existing socket name isn't "active".
 			## -> Type: If the existing socket_type != "active" SocketDef.
 			bl_sockets_to_remove = [
-				bl_socket
+				active_sckname
-				for socket_name, bl_socket in bl_sockets.items()
+				for active_sckname, active_scktype in active_socket_nametype.items()
 				if (
-					socket_name not in active_socket_defs
+					active_sckname not in active_socket_defs
-					or bl_socket.socket_type
+					or active_scktype
-					is not active_socket_defs[socket_name].socket_type
+					is not active_socket_defs[active_sckname].socket_type
 				)
 			]
 
@@ -394,39 +397,50 @@ class MaxwellSimNode(bpy.types.Node, bl_instance.BLInstance):
 			## -> Name: If the existing socket name is "active".
 			## -> Type: If the existing socket_type == "active" SocketDef.
 			## -> Compare: If the existing socket differs from the SocketDef.
+			## -> NOTE: Reload bl_sockets in case to-update scks were removed.
 			bl_sockets_to_update = [
-				bl_socket
+				active_sckname
-				for socket_name, bl_socket in bl_sockets.items()
+				for active_sckname, active_scktype in active_socket_nametype.items()
 				if (
-					socket_name in active_socket_defs
+					active_sckname in active_socket_defs
-					and bl_socket.socket_type
+					and active_scktype is active_socket_defs[active_sckname].socket_type
-					is active_socket_defs[socket_name].socket_type
+					and not active_socket_defs[active_sckname].compare(
-					and not active_socket_defs[socket_name].compare(bl_socket)
+						self._bl_sockets(direc)[active_sckname]
+					)
 				)
 			]
 
 			# Remove Sockets
-			for bl_socket in bl_sockets_to_remove:
+			## -> The symptom of using a deleted socket is... hard crash.
-				bl_socket_name = bl_socket.name
+			## -> Therefore, we must be EXTREMELY careful with bl_socket refs.
+			## -> The multi-stage for-loop helps us guard from deleted sockets.
+			for active_sckname in bl_sockets_to_remove:
+				bl_socket = self._bl_sockets(direc).get(active_sckname)
 
 				# 1. Report the socket removal to the NodeTree.
 				## -> The NodeLinkCache needs to be adjusted manually.
 				node_tree.on_node_socket_removed(bl_socket)
 
+			for active_sckname in bl_sockets_to_remove:
+				bl_sockets = self._bl_sockets(direc)
+				bl_socket = bl_sockets.get(active_sckname)
+
 				# 2. Perform the removal using Blender's API.
 				## -> Actually removes the socket.
-				bl_sockets.remove(bl_socket)
+				## -> Must be protected from auto-removed use-after-free.
-
+				if bl_socket is not None:
-				# 3. Invalidate the input socket cache across all kinds.
+					bl_sockets.remove(bl_socket)
-				## -> Prevents phantom values from remaining available.
-				## -> Done after socket removal to protect from race condition.
-				self._compute_input.invalidate(
-					input_socket_name=bl_socket_name,
-					kind=...,
-					unit_system=...,
-				)
 
 				if direc == 'input':
+					# 3. Invalidate the input socket cache across all kinds.
+					## -> Prevents phantom values from remaining available.
+					## -> Done after socket removal to protect from race condition.
+					self._compute_input.invalidate(
+						input_socket_name=active_sckname,
+						kind=...,
+						unit_system=...,
+					)
+
 					# 4. Run all trigger-only `on_value_changed` callbacks.
 					## -> Runs any event methods that relied on the socket.
 					## -> Only methods that don't **require** the socket.
@@ -435,39 +449,69 @@ class MaxwellSimNode(bpy.types.Node, bl_instance.BLInstance):
 					triggered_event_methods = [
 						event_method
 						for event_method in self.filtered_event_methods_by_event(
-							ct.FlowEvent.DataChanged, (bl_socket_name, None, None)
+							ct.FlowEvent.DataChanged, (active_sckname, None, None)
 						)
-						if bl_socket_name
+						if active_sckname
 						not in event_method.callback_info.must_load_sockets
 					]
 					for event_method in triggered_event_methods:
 						event_method(self)
 
+				else:
+					# 3. Invalidate the output socket cache across all kinds.
+					## -> Prevents phantom values from remaining available.
+					## -> Done after socket removal to protect from race condition.
+					self.compute_output.invalidate(
+						input_socket_name=active_sckname,
+						kind=...,
+					)
+
 			# Update Sockets
-			for bl_socket in bl_sockets_to_update:
+			## -> The symptom of using a deleted socket is... hard crash.
-				bl_socket_name = bl_socket.name
+			## -> Therefore, we must be EXTREMELY careful with bl_socket refs.
-				socket_def = active_socket_defs[bl_socket_name]
+			## -> The multi-stage for-loop helps us guard from deleted sockets.
+			for active_sckname in bl_sockets_to_update:
+				bl_sockets = self._bl_sockets(direc)
+				bl_socket = bl_sockets.get(active_sckname)
 
-				# 1. Pretend to Initialize for the First Time
+				if bl_socket is not None:
-				## -> NOTE: The socket's caches will be completely regenerated.
+					socket_def = active_socket_defs[active_sckname]
-				## -> NOTE: A full FlowKind update will occur, but only one.
-				bl_socket.is_initializing = True
-				socket_def.preinit(bl_socket)
-				socket_def.init(bl_socket)
-				socket_def.postinit(bl_socket)
 
-				# 2. Re-Test Socket Capabilities
+					# 1. Pretend to Initialize for the First Time
-				## -> Factors influencing CapabilitiesFlow may have changed.
+					## -> NOTE: The socket's caches will be completely regenerated.
-				## -> Therefore, we must re-test all link capabilities.
+					## -> NOTE: A full FlowKind update will occur, but only one.
-				bl_socket.remove_invalidated_links()
+					bl_socket.is_initializing = True
+					socket_def.preinit(bl_socket)
+					socket_def.init(bl_socket)
+					socket_def.postinit(bl_socket)
 
-				# 3. Invalidate the input socket cache across all kinds.
+			for active_sckname in bl_sockets_to_update:
-				## -> Prevents phantom values from remaining available.
+				bl_sockets = self._bl_sockets(direc)
-				self._compute_input.invalidate(
+				bl_socket = bl_sockets.get(active_sckname)
-					input_socket_name=bl_socket_name,
+
-					kind=...,
+				if bl_socket is not None:
-					unit_system=...,
+					# 2. Re-Test Socket Capabilities
-				)
+					## -> Factors influencing CapabilitiesFlow may have changed.
+					## -> Therefore, we must re-test all link capabilities.
+					bl_socket.remove_invalidated_links()
+
+					if direc == 'input':
+						# 3. Invalidate the input socket cache across all kinds.
+						## -> Prevents phantom values from remaining available.
+						self._compute_input.invalidate(
+							input_socket_name=active_sckname,
+							kind=...,
+							unit_system=...,
+						)
+
+					if direc == 'output':
+						# 3. Invalidate the output socket cache across all kinds.
+						## -> Prevents phantom values from remaining available.
+						## -> Done after socket removal to protect from race condition.
+						self.compute_output.invalidate(
+							input_socket_name=active_sckname,
+							kind=...,
+						)
 
 	def _add_new_active_sockets(self):
 		"""Add and initialize all "active" sockets that aren't on the node.

src/blender_maxwell/node_trees/maxwell_sim_nodes/nodes/inputs/constants/symbol_constant.py

@@ -104,6 +104,11 @@ class SymbolConstantNode(base.MaxwellSimNode):
 	interval_inf_im: tuple[bool, bool] = bl_cache.BLField((True, True))
 	interval_closed_im: tuple[bool, bool] = bl_cache.BLField((True, True))
 
+	preview_value_z: int = bl_cache.BLField(0)
+	preview_value_q: tuple[int, int] = bl_cache.BLField((0, 1))
+	preview_value_re: float = bl_cache.BLField(0.0)
+	preview_value_im: float = bl_cache.BLField(0.0)
+
 	####################
 	# - Computed Properties
 	####################
@@ -122,6 +127,10 @@ class SymbolConstantNode(base.MaxwellSimNode):
 			'interval_finite_im',
 			'interval_inf_im',
 			'interval_closed_im',
+			'preview_value_z',
+			'preview_value_q',
+			'preview_value_re',
+			'preview_value_im',
 		}
 	)
 	def symbol(self) -> sim_symbols.SimSymbol:
@@ -140,6 +149,10 @@ class SymbolConstantNode(base.MaxwellSimNode):
 			interval_finite_im=self.interval_finite_im,
 			interval_inf_im=self.interval_inf_im,
 			interval_closed_im=self.interval_closed_im,
+			preview_value_z=self.preview_value_z,
+			preview_value_q=self.preview_value_q,
+			preview_value_re=self.preview_value_re,
+			preview_value_im=self.preview_value_im,
 		)
 
 	####################
@@ -164,36 +177,68 @@ class SymbolConstantNode(base.MaxwellSimNode):
 
 		col.prop(self, self.blfields['physical_type'], text='')
 
+		# Domain - Infinite
 		row = col.row(align=True)
 		row.alignment = 'CENTER'
-		row.label(text='Domain')
+		row.label(text='Domain - Is Infinite')
 
+		row = col.row(align=True)
+		if self.mathtype is spux.MathType.Complex:
+			row.prop(self, self.blfields['interval_inf'], text='ℝ')
+			row.prop(self, self.blfields['interval_inf_im'], text='𝕀')
+		else:
+			row.prop(self, self.blfields['interval_inf'], text='')
+
+		if any(not b for b in self.interval_inf):
+			# Domain - Closure
+			row = col.row(align=True)
+			row.alignment = 'CENTER'
+			row.label(text='Domain - Closure')
+
+			row = col.row(align=True)
+			if self.mathtype is spux.MathType.Complex:
+				row.prop(self, self.blfields['interval_closed'], text='ℝ')
+				row.prop(self, self.blfields['interval_closed_im'], text='𝕀')
+			else:
+				row.prop(self, self.blfields['interval_closed'], text='')
+
+			# Domain - Finite
+			row = col.row(align=True)
+			row.alignment = 'CENTER'
+			row.label(text='Domain - Interval')
+
+			row = col.row(align=True)
+			match self.mathtype:
+				case spux.MathType.Integer:
+					row.prop(self, self.blfields['interval_finite_z'], text='')
+
+				case spux.MathType.Rational:
+					row.prop(self, self.blfields['interval_finite_q'], text='')
+
+				case spux.MathType.Real:
+					row.prop(self, self.blfields['interval_finite_re'], text='')
+
+				case spux.MathType.Complex:
+					row.prop(self, self.blfields['interval_finite_re'], text='ℝ')
+					row.prop(self, self.blfields['interval_finite_im'], text='𝕀')
+
+		# Domain - Closure
+		row = col.row(align=True)
+		row.alignment = 'CENTER'
+		row.label(text='Preview Value')
 		match self.mathtype:
 			case spux.MathType.Integer:
-				col.prop(self, self.blfields['interval_finite_z'], text='')
+				row.prop(self, self.blfields['preview_value_z'], text='')
-				col.prop(self, self.blfields['interval_inf'], text='Infinite')
-				col.prop(self, self.blfields['interval_closed'], text='Closed')
 
 			case spux.MathType.Rational:
-				col.prop(self, self.blfields['interval_finite_q'], text='')
+				row.prop(self, self.blfields['preview_value_q'], text='')
-				col.prop(self, self.blfields['interval_inf'], text='Infinite')
-				col.prop(self, self.blfields['interval_closed'], text='Closed')
 
 			case spux.MathType.Real:
-				col.prop(self, self.blfields['interval_finite_re'], text='')
+				row.prop(self, self.blfields['preview_value_re'], text='')
-				col.prop(self, self.blfields['interval_inf'], text='Infinite')
-				col.prop(self, self.blfields['interval_closed'], text='Closed')
 
 			case spux.MathType.Complex:
-				col.prop(self, self.blfields['interval_finite_re'], text='ℝ')
+				row.prop(self, self.blfields['preview_value_re'], text='ℝ')
-				col.prop(self, self.blfields['interval_inf'], text='ℝ Infinite')
+				row.prop(self, self.blfields['preview_value_im'], text='𝕀')
-				col.prop(self, self.blfields['interval_closed'], text='ℝ Closed')
-
-				col.separator()
-
-				col.prop(self, self.blfields['interval_finite_im'], text='𝕀')
-				col.prop(self, self.blfields['interval_inf'], text='𝕀 Infinite')
-				col.prop(self, self.blfields['interval_closed'], text='𝕀 Closed')
 
 	####################
 	# - FlowKinds

src/blender_maxwell/node_trees/maxwell_sim_nodes/nodes/simulations/sim_domain.py

@@ -132,7 +132,7 @@ class SimDomainNode(base.MaxwellSimNode):
 				| grid
 				| medium
 			).compose_within(
-				enclosing_func=lambda els: {
+				lambda els: {
 					'run_time': els[0],
 					'center': tuple(els[1].flatten()),
 					'size': tuple(els[2].flatten()),

src/blender_maxwell/node_trees/maxwell_sim_nodes/nodes/structures/primitives/box_structure.py

@@ -88,36 +88,19 @@ class BoxStructureNode(base.MaxwellSimNode):
 		'Structure',
 		kind=ct.FlowKind.Value,
 		# Loaded
-		input_sockets={'Medium', 'Center', 'Size'},
 		output_sockets={'Structure'},
-		output_socket_kinds={'Structure': ct.FlowKind.Params},
+		output_socket_kinds={'Structure': {ct.FlowKind.Func, ct.FlowKind.Params}},
 	)
-	def compute_value(self, input_sockets, output_sockets) -> td.Box:
+	def compute_value(self, output_sockets) -> ct.ParamsFlow | ct.FlowSignal:
-		"""Compute a single box structure object, given that all inputs are non-symbolic."""
+		"""Compute the particular value of the simulation domain from strictly non-symbolic inputs."""
-		center = input_sockets['Center']
+		output_func = output_sockets['Structure'][ct.FlowKind.Func]
-		size = input_sockets['Size']
+		output_params = output_sockets['Structure'][ct.FlowKind.Params]
-		medium = input_sockets['Medium']
-		output_params = output_sockets['Structure']
 
-		has_center = not ct.FlowSignal.check(center)
+		has_output_func = not ct.FlowSignal.check(output_func)
-		has_size = not ct.FlowSignal.check(size)
-		has_medium = not ct.FlowSignal.check(medium)
 		has_output_params = not ct.FlowSignal.check(output_params)
 
-		if (
+		if has_output_func and has_output_params and not output_params.symbols:
-			has_center
+			return output_func.realize(output_params, disallow_jax=True)
-			and has_size
-			and has_medium
-			and has_output_params
-			and not output_params.symbols
-		):
-			return td.Structure(
-				geometry=td.Box(
-					center=spux.scale_to_unit_system(center, ct.UNITS_TIDY3D),
-					size=spux.scale_to_unit_system(size, ct.UNITS_TIDY3D),
-				),
-				medium=medium,
-			)
 		return ct.FlowSignal.FlowPending
 
 	####################
@@ -134,45 +117,43 @@ class BoxStructureNode(base.MaxwellSimNode):
 			'Center': ct.FlowKind.Func,
 			'Size': ct.FlowKind.Func,
 		},
-		output_sockets={'Structure'},
-		output_socket_kinds={'Structure': ct.FlowKind.Params},
 	)
-	def compute_structure_func(self, props, input_sockets, output_sockets) -> td.Box:
+	def compute_structure_func(self, props, input_sockets) -> td.Box:
 		"""Compute a possibly-differentiable function, producing a box structure from the input parameters."""
-		output_params = output_sockets['Structure']
 		center = input_sockets['Center']
 		size = input_sockets['Size']
 		medium = input_sockets['Medium']
 
-		has_output_params = not ct.FlowSignal.check(output_params)
 		has_center = not ct.FlowSignal.check(center)
 		has_size = not ct.FlowSignal.check(size)
 		has_medium = not ct.FlowSignal.check(medium)
 
-		if has_output_params and has_center and has_size and has_medium:
+		if has_center and has_size and has_medium:
 			differentiable = props['differentiable']
 			if differentiable:
-				return (center | size | medium).compose_within(
+				return (
-					enclosing_func=lambda els: tdadj.JaxStructure(
+					center.scale_to_unit_system(ct.UNITS_TIDY3D)
+					| size.scale_to_unit_system(ct.UNITS_TIDY3D)
+					| medium
+				).compose_within(
+					lambda els: tdadj.JaxStructure(
 						geometry=tdadj.JaxBox(
-							center=tuple(els[0].flatten()),
+							center_jax=tuple(els[0].flatten()),
-							size=tuple(els[1].flatten()),
+							size_jax=tuple(els[1].flatten()),
 						),
 						medium=els[2],
 					),
 					supports_jax=True,
 				)
-			return (center | size | medium).compose_within(
+			return (
-				## TODO: Unit conversion within the composed function??
+				center.scale_to_unit_system(ct.UNITS_TIDY3D)
-				## -- We do need Tidy3D to be given ex. micrometers in particular.
+				| size.scale_to_unit_system(ct.UNITS_TIDY3D)
-				## -- But the previous numerical output might not be micrometers.
+				| medium
-				## -- There must be a way to add a conversion in, without strangeness.
+			).compose_within(
-				## -- Ex. can compose_within() take a unit system?
+				lambda els: td.Structure(
-				## -- This would require
-				enclosing_func=lambda els: td.Structure(
 					geometry=td.Box(
-						center=tuple(els[0].flatten()),
+						center=els[0].flatten().tolist(),
-						size=tuple(els[1].flatten()),
+						size=els[1].flatten().tolist(),
 					),
 					medium=els[2],
 				),
@@ -187,7 +168,6 @@ class BoxStructureNode(base.MaxwellSimNode):
 		'Structure',
 		kind=ct.FlowKind.Params,
 		# Loaded
-		props={'differentiable'},
 		input_sockets={'Medium', 'Center', 'Size'},
 		input_socket_kinds={
 			'Medium': ct.FlowKind.Params,
@@ -195,7 +175,7 @@ class BoxStructureNode(base.MaxwellSimNode):
 			'Size': ct.FlowKind.Params,
 		},
 	)
-	def compute_params(self, props, input_sockets) -> td.Box:
+	def compute_params(self, input_sockets) -> td.Box:
 		center = input_sockets['Center']
 		size = input_sockets['Size']
 		medium = input_sockets['Medium']
@@ -238,13 +218,16 @@ class BoxStructureNode(base.MaxwellSimNode):
 		output_sockets={'Structure'},
 		output_socket_kinds={'Structure': ct.FlowKind.Params},
 	)
-	def on_inputs_changed(self, managed_objs, input_sockets, output_sockets):
+	def on_previewable_changed(self, managed_objs, input_sockets, output_sockets):
-		output_params = output_sockets['Structure']
 		center = input_sockets['Center']
+		size = input_sockets['Size']
+		output_params = output_sockets['Structure']
 
-		has_output_params = not ct.FlowSignal.check(output_params)
 		has_center = not ct.FlowSignal.check(center)
-		if has_center and has_output_params and not output_params.symbols:
+		has_size = not ct.FlowSignal.check(size)
+		has_output_params = not ct.FlowSignal.check(output_params)
+
+		if has_center and has_size and has_output_params and not output_params.symbols:
 			## TODO: There are strategies for handling examples of symbol values.
 
 			# Push Loose Input Values to GeoNodes Modifier
@@ -254,7 +237,7 @@ class BoxStructureNode(base.MaxwellSimNode):
 					'node_group': import_geonodes(GeoNodes.StructurePrimitiveBox),
 					'unit_system': ct.UNITS_BLENDER,
 					'inputs': {
-						'Size': input_sockets['Size'],
+						'Size': size,
 					},
 				},
 				location=spux.scale_to_unit_system(center, ct.UNITS_BLENDER),

src/blender_maxwell/node_trees/maxwell_sim_nodes/nodes/structures/primitives/cylinder_structure.py

@@ -32,6 +32,8 @@ log = logger.get(__name__)
 
 
 class CylinderStructureNode(base.MaxwellSimNode):
+	"""A generic cylinder structure with configurable radius and height."""
+
 	node_type = ct.NodeType.CylinderStructure
 	bl_label = 'Cylinder Structure'
 	use_sim_node_name = True
@@ -64,27 +66,101 @@ class CylinderStructureNode(base.MaxwellSimNode):
 	}
 
 	####################
-	# - Output Socket Computation
+	# - FlowKind.Value
 	####################
 	@events.computes_output_socket(
 		'Structure',
+		kind=ct.FlowKind.Value,
+		# Loaded
+		output_sockets={'Structure'},
+		output_socket_kinds={'Structure': {ct.FlowKind.Func, ct.FlowKind.Params}},
+	)
+	def compute_value(self, output_sockets) -> ct.ParamsFlow | ct.FlowSignal:
+		"""Compute the particular value of the simulation domain from strictly non-symbolic inputs."""
+		output_func = output_sockets['Structure'][ct.FlowKind.Func]
+		output_params = output_sockets['Structure'][ct.FlowKind.Params]
+
+		has_output_func = not ct.FlowSignal.check(output_func)
+		has_output_params = not ct.FlowSignal.check(output_params)
+
+		if has_output_func and has_output_params and not output_params.symbols:
+			return output_func.realize(output_params, disallow_jax=True)
+		return ct.FlowSignal.FlowPending
+
+	####################
+	# - FlowKind.Func
+	####################
+	@events.computes_output_socket(
+		'Structure',
+		kind=ct.FlowKind.Func,
+		# Loaded
 		input_sockets={'Center', 'Radius', 'Medium', 'Height'},
-		unit_systems={'Tidy3DUnits': ct.UNITS_TIDY3D},
+		input_socket_kinds={
-		scale_input_sockets={
+			'Center': ct.FlowKind.Func,
-			'Center': 'Tidy3DUnits',
+			'Radius': ct.FlowKind.Func,
-			'Radius': 'Tidy3DUnits',
+			'Height': ct.FlowKind.Func,
-			'Height': 'Tidy3DUnits',
+			'Medium': ct.FlowKind.Func,
 		},
 	)
-	def compute_structure(self, input_sockets, unit_systems) -> td.Box:
+	def compute_func(self, input_sockets) -> td.Box:
-		return td.Structure(
+		"""Compute a single cylinder structure object, given that all inputs are non-symbolic."""
-			geometry=td.Cylinder(
+		center = input_sockets['Center']
-				radius=input_sockets['Radius'],
+		radius = input_sockets['Radius']
-				center=input_sockets['Center'],
+		height = input_sockets['Height']
-				length=input_sockets['Height'],
+		medium = input_sockets['Medium']
-			),
+
-			medium=input_sockets['Medium'],
+		has_center = not ct.FlowSignal.check(center)
-		)
+		has_radius = not ct.FlowSignal.check(radius)
+		has_height = not ct.FlowSignal.check(height)
+		has_medium = not ct.FlowSignal.check(medium)
+
+		if has_center and has_radius and has_height and has_medium:
+			return (
+				center.scale_to_unit_system(ct.UNITS_TIDY3D)
+				| radius.scale_to_unit_system(ct.UNITS_TIDY3D)
+				| height.scale_to_unit_system(ct.UNITS_TIDY3D)
+				| medium
+			).compose_within(
+				lambda els: td.Structure(
+					geometry=td.Cylinder(
+						center=els[0].flatten().tolist(),
+						radius=els[1],
+						length=els[2],
+					),
+					medium=els[3],
+				)
+			)
+		return ct.FlowSignal.FlowPending
+
+	####################
+	# - FlowKind.Params
+	####################
+	@events.computes_output_socket(
+		'Structure',
+		kind=ct.FlowKind.Params,
+		# Loaded
+		input_sockets={'Center', 'Radius', 'Medium', 'Height'},
+		input_socket_kinds={
+			'Center': ct.FlowKind.Params,
+			'Radius': ct.FlowKind.Params,
+			'Height': ct.FlowKind.Params,
+			'Medium': ct.FlowKind.Params,
+		},
+	)
+	def compute_params(self, input_sockets) -> td.Box:
+		center = input_sockets['Center']
+		radius = input_sockets['Radius']
+		height = input_sockets['Height']
+		medium = input_sockets['Medium']
+
+		has_center = not ct.FlowSignal.check(center)
+		has_radius = not ct.FlowSignal.check(radius)
+		has_height = not ct.FlowSignal.check(height)
+		has_medium = not ct.FlowSignal.check(medium)
+
+		if has_center and has_radius and has_height and has_medium:
+			return center | radius | height | medium
+		return ct.FlowSignal.FlowPending
 
 	####################
 	# - Preview

src/blender_maxwell/node_trees/maxwell_sim_nodes/sockets/expr.py

@@ -791,14 +791,7 @@ class ExprBLSocket(base.MaxwellSimSocket):
 	####################
 	# - FlowKind: Func (w/Params if Constant)
 	####################
-	@bl_cache.cached_bl_property(
+	@bl_cache.cached_bl_property(depends_on={'output_sym'})
-		depends_on={
-			'value',
-			'sorted_sp_symbols',
-			'sorted_symbols',
-			'output_sym',
-		}
-	)
 	def lazy_func(self) -> ct.FuncFlow:
 		"""Returns a lazy value that computes the expression returned by `self.value`.
 
@@ -806,42 +799,12 @@ class ExprBLSocket(base.MaxwellSimSocket):
 		Otherwise, the returned lazy value function will be a simple excuse for `self.params` to pass the verbatim `self.value`.
 		"""
 		if self.output_sym is not None:
-			match self.active_kind:
+			return ct.FuncFlow(
-				case ct.FlowKind.Value | ct.FlowKind.Func if (
+				func=lambda v: v,
-					self.sorted_symbols and not ct.FlowSignal.check(self.value)
+				func_args=[self.output_sym],
-				):
+				func_output=self.output_sym,
-					return ct.FuncFlow(
+				supports_jax=True,
-						func=sp.lambdify(
+			)
-							self.sorted_sp_symbols,
-							self.output_sym.conform(self.value, strip_unit=True),
-							'jax',
-						),
-						func_args=list(self.sorted_symbols),
-						func_output=self.output_sym,
-						supports_jax=True,
-					)
-
-				case ct.FlowKind.Value | ct.FlowKind.Func if not self.sorted_symbols:
-					return ct.FuncFlow(
-						func=lambda v: v,
-						func_args=[self.output_sym],
-						func_output=self.output_sym,
-						supports_jax=True,
-					)
-
-				case ct.FlowKind.Range if self.sorted_symbols:
-					msg = 'RangeFlow support not yet implemented for when self.sorted_symbols is not empty'
-					raise NotImplementedError(msg)
-
-				case ct.FlowKind.Range if (
-					not self.sorted_symbols and not ct.FlowSignal.check(self.lazy_range)
-				):
-					return ct.FuncFlow(
-						func=lambda v: v,
-						func_args=[self.output_sym],
-						func_output=self.output_sym,
-						supports_jax=True,
-					)
 
 		return ct.FlowSignal.FlowPending
 
@@ -854,22 +817,15 @@ class ExprBLSocket(base.MaxwellSimSocket):
 		If `self.value` has unknown symbols (as indicated by `self.symbols`), then these will be passed into `ParamsFlow`, which will thus be parameterized (and require realization before use).
 		Otherwise, `self.value` is passed verbatim as the only `ParamsFlow.func_arg`.
 		"""
-		output_sym = self.output_sym
+		if self.output_sym is not None:
-		if output_sym is not None:
 			match self.active_kind:
-				case ct.FlowKind.Value | ct.FlowKind.Func if self.sorted_symbols:
-					return ct.ParamsFlow(
-						arg_targets=list(self.sorted_symbols),
-						func_args=[sym.sp_symbol for sym in self.sorted_symbols],
-						symbols=set(self.sorted_symbols),
-					)
-
 				case ct.FlowKind.Value | ct.FlowKind.Func if (
-					not self.sorted_symbols and not ct.FlowSignal.check(self.value)
+					not ct.FlowSignal.check(self.value)
 				):
 					return ct.ParamsFlow(
 						arg_targets=[self.output_sym],
 						func_args=[self.value],
+						symbols=set(self.sorted_symbols),
 					)
 
 				case ct.FlowKind.Range if self.sorted_symbols:
@@ -899,20 +855,14 @@ class ExprBLSocket(base.MaxwellSimSocket):
 
 		Otherwise, only the output name/size/mathtype/unit corresponding to the socket is passed along.
 		"""
-		output_sym = self.output_sym
+		if self.output_sym is not None:
-		if output_sym is not None:
 			match self.active_kind:
-				case ct.FlowKind.Value | ct.FlowKind.Func if self.sorted_symbols:
+				case ct.FlowKind.Value | ct.FlowKind.Func:
 					return ct.InfoFlow(
 						dims={sym: None for sym in self.sorted_symbols},
 						output=self.output_sym,
 					)
 
-				case ct.FlowKind.Value | ct.FlowKind.Func if (
-					not self.sorted_symbols and not ct.FlowSignal.check(self.lazy_range)
-				):
-					return ct.InfoFlow(output=self.output_sym)
-
 				case ct.FlowKind.Range if self.sorted_symbols:
 					msg = 'InfoFlow support not yet implemented for when self.sorted_symbols is not empty'
 					raise NotImplementedError(msg)

src/blender_maxwell/node_trees/maxwell_sim_nodes/sockets/maxwell/medium.py

@@ -14,7 +14,10 @@
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
+import math
+
 import bpy
+import jax.numpy as jnp
 import scipy as sc
 import sympy.physics.units as spu
 import tidy3d as td
@@ -28,9 +31,15 @@ from .. import base
 
 log = logger.get(__name__)
 
-VAC_SPEED_OF_LIGHT = sc.constants.speed_of_light * spu.meter / spu.second
+_VAC_SPEED_OF_LIGHT = sc.constants.speed_of_light * spu.meter / spu.second
-
+_FIXED_WL = 500 * spu.nm
-FIXED_WL = 500 * spu.nm
+FIXED_FREQ = spux.scale_to_unit_system(
+	spu.convert_to(
+		_VAC_SPEED_OF_LIGHT / _FIXED_WL,
+		spu.hertz,
+	),
+	ct.UNITS_TIDY3D,
+)
 
 
 class MaxwellMediumBLSocket(base.MaxwellSimSocket):
@@ -49,24 +58,17 @@ class MaxwellMediumBLSocket(base.MaxwellSimSocket):
 	####################
 	@bl_cache.cached_bl_property(depends_on={'eps_rel', 'differentiable'})
 	def value(self) -> td.Medium:
-		freq = (
+		eps_r_re = self.eps_rel[0]
-			spu.convert_to(
+		conductivity = FIXED_FREQ * self.eps_rel[1]  ## TODO: Um?
-				VAC_SPEED_OF_LIGHT / FIXED_WL,
-				spu.hertz,
-			)
-			/ spu.hertz
-		)
 
 		if self.differentiable:
-			return tdadj.JaxMedium.from_nk(
+			return tdadj.JaxMedium(
-				n=self.eps_rel[0],
+				permittivity_jax=jnp.array(eps_r_re, dtype=float),
-				k=self.eps_rel[1],
+				conductivity_jax=jnp.array(conductivity, dtype=float),
-				freq=freq,
 			)
-		return td.Medium.from_nk(
+		return td.Medium(
-			n=self.eps_rel[0],
+			permittivity=eps_r_re,
-			k=self.eps_rel[1],
+			conductivity=conductivity,
-			freq=freq,
 		)
 
 	@value.setter

src/blender_maxwell/utils/sim_symbols.py

@@ -263,6 +263,11 @@ class SimSymbol(pyd.BaseModel):
 	interval_inf_im: tuple[bool, bool] = (True, True)
 	interval_closed_im: tuple[bool, bool] = (False, False)
 
+	preview_value_z: int = 0
+	preview_value_q: tuple[int, int] = (0, 1)
+	preview_value_re: float = 0.0
+	preview_value_im: float = 0.0
+
 	####################
 	# - Core
 	####################