Merge #30 into xts_origin from refs/changes/30/head

Merge #30 into xts_origin from refs/changes/30/head

Code review from 袁清梦

* refs/changes/30/head: (2 commits squashed)

  - 优化训练back逻辑

  - Merge branch 'xts_origin' of https://codeup.aliyun.com/64191456b9581d62e8f81ac0/FD230 into xts_origin

Signed-off-by: Caisking <3449750381@qq.com>
Reviewed-by: snickersun@163.com <accounts_62b90f7fcf51ade33b6f628e@mail.teambition.com>
Merged-by: snickersun@163.com <accounts_62b90f7fcf51ade33b6f628e@mail.teambition.com>
link: https://codeup.aliyun.com/64191456b9581d62e8f81ac0/FD230/change/30