* refactor the optional tensor

* remove optiona<MetaTensor> in InferMeta

* fix bug

* fix optional<vector<Tensor>>

* fix bug

* fix rmsprop

* fix amp of eager_gen

* polish code

* fix deleted code

* fix merge conflict

* polish code

* remove is_nullopt_

* fix merge conflict

* fix merge conflict

* Add yaml config

* Add yaml for flatten_contiguous_range_op

* Remove h_sigmoid yaml

* Fix CI errors

* Fix code format

* Fix flatten OP errors

* Fix conflicts

* Fix CI errors

* Remove flatten_contiguous_range OP

* Remove redundant code

* Fix typos

* first commit

* fix compile error

* support std::vector<std::srting>

* fix

* fix op support on GPU by chenweihang

* pass test

* infershape

* add set_dtype

* fix order

* fix

* unify the impl of dt and sr

* fix