Try it .
@api.multi
@api.onchange('val1','val2')
def onchange_calculer(self):
for s in self:
s.list_price = s.val1 * (s.val2/100) + s.val1
Where val1 and val2 are fields of product.template object and onchage_calculer will start when detect any change in val1 and val2 fields values.
sorry for my english.
P.D: the fields.float('') sintax works in v11 ?
