quantities.py 文件源码

def _collect_factor_and_dimension(expr):

        if isinstance(expr, Quantity):
            return expr.scale_factor, expr.dimension
        elif isinstance(expr, Mul):
            factor = 1
            dimension = 1
            for arg in expr.args:
                arg_factor, arg_dim = Quantity._collect_factor_and_dimension(arg)
                factor *= arg_factor
                dimension *= arg_dim
            return factor, dimension
        elif isinstance(expr, Pow):
            factor, dim = Quantity._collect_factor_and_dimension(expr.base)
            return factor ** expr.exp, dim ** expr.exp
        elif isinstance(expr, Add):
            raise NotImplementedError
        else:
            return 1, 1