diff --git a/src/kyupy/sdf.py b/src/kyupy/sdf.py
index f11e932..528b48c 100644
--- a/src/kyupy/sdf.py
+++ b/src/kyupy/sdf.py
@@ -59,7 +59,7 @@ class DelayFile:
             if name not in circuit.cells: name = name.replace('[', '_').replace(']', '_')
             return circuit.cells.get(name, None)
 
-        delays = np.zeros((len(circuit.lines), 2, 2, 3))  # dataset last during construction.
+        delays = np.zeros((len(circuit.lines), 2, 2, 3), dtype=np.float32)  # dataset last during construction.
 
         with log.limit(50):
             for name, iopaths in self.cells.items():
@@ -101,14 +101,19 @@ class DelayFile:
         * Axis 3: polarity of the transition, 0='rising/posedge', 1='falling/negedge'
         """
 
-        delays = np.zeros((len(circuit.lines), 2, 2, 3))  # dataset last during construction.
+        delays = np.zeros((len(circuit.lines), 2, 2, 3), dtype=np.float32)  # dataset last during construction.
+
+        def split_node_port(n_str):
+            if (split := n_str.rfind('.')) > 0 or (split := n_str.rfind('/')) > 0:
+                return n_str[:split], n_str[split+1:]
+            return (n_str, None)
 
         nonfork_annotations = 0
         for n1, n2, *delvals in self._interconnects:
             delvals = [d if len(d) > 0 else [0, 0, 0] for d in delvals]
             if max(max(delvals)) == 0: continue
-            cn1, pn1 = (n1, None) if (slash := n1.rfind('/')) < 0 else (n1[:slash], n1[slash+1:])
-            cn2, pn2 = (n2, None) if (slash := n2.rfind('/')) < 0 else (n2[:slash], n2[slash+1:])
+            cn1, pn1 = split_node_port(n1)
+            cn2, pn2 = split_node_port(n2)
             cn1 = cn1.replace('\\','')
             cn2 = cn2.replace('\\','')
             c1, c2 = circuit.cells[cn1], circuit.cells[cn2]