utils.py 文件源码

def non_commutative_symexpand(expr_string):
    from sympy.parsing.sympy_parser import parse_expr
    parsed_expr = parse_expr(expr_string, evaluate=False)
    new_locals = {sym.name:sympy.Symbol(sym.name, commutative=False)
                  for sym in parsed_expr.atoms(sympy.Symbol)}
    return sympy.expand(eval(expr_string, {}, new_locals))