hilbert.py 文件源码

def eval(cls, args):
        new_args = args[0], sympify(args[1])
        exp = new_args[1]
        #simplify hs**1 -> hs
        if exp == 1:
            return args[0]
        #simplify hs**0 -> 1
        if exp == 0:
            return sympify(1)
        #check (and allow) for hs**(x+42+y...) case
        if len(exp.atoms()) == 1:
            if not (exp.is_Integer and exp >= 0 or exp.is_Symbol):
                raise ValueError('Hilbert spaces can only be raised to \
                positive integers or Symbols: %r' % exp)
        else:
            for power in exp.atoms():
                if not (power.is_Integer or power.is_Symbol):
                    raise ValueError('Tensor powers can only contain integers \
                    or Symbols: %r' % power)
        return new_args