因为这样会减少精度误差(据说)
by Uzumaki @ 2021-11-05 17:14:46
数值稳定性,代数上不关心,只要非零即可。
by hly1204 @ 2021-11-05 18:33:47
@[SenriAkane](/user/396400) 不换也能 A(亲测
by Zvelig1205 @ 2021-11-10 16:01:17