operatorordering.py 文件源码

def _normal_ordered_form_terms(expr, independent=False, recursive_limit=10,
                               _recursive_depth=0):
    """
    Helper function for normal_ordered_form: loop through each term in an
    addition expression and call _normal_ordered_form_factor to perform the
    factor to an normally ordered expression.
    """

    new_terms = []
    for term in expr.args:
        if isinstance(term, Mul):
            new_term = _normal_ordered_form_factor(
                term, recursive_limit=recursive_limit,
                _recursive_depth=_recursive_depth, independent=independent)
            new_terms.append(new_term)
        else:
            new_terms.append(term)

    return Add(*new_terms)