ignore `NA` if casting to param.REAL
@@ -60,7 +60,7 @@ def initialize_field(filename, param, field=None):
for key in ['E', 'kappa']:
for i, e in enumerate(field[key]):
- if not isinstance(e, complex):
+ if not isinstance(e, complex) and not isinstance(e, str):
field[key][i] = param.REAL(field[key][i])
Nfield = len(field['LorY'])
