zero init

app.py

@@ -120,8 +120,9 @@ def run(duration, resolution, pitch, glissando, vibrato, stiffness, tension, plu
     
     params, f_0, u_0 = get_data( \
         duration, resolution, pitch, glissando, vibrato, stiffness, tension, pluck, amplitude)
+
     if torch.cuda.is_available():
-        params = [p.cuda() for p in params]
+        params = [p.cuda() if p is not None else p for p in params]
         f_0 = f_0.cuda()
         u_0 = u_0.cuda()