* rename kernel

* delete sig

* modify code according comment

* fix ci bugs

* Einsum Support Complex

* code fix

* add unittest for complex grad with einsum

* set rtol=1e-4

* fix

* add unittest for einsum-v2-trace and diagonal

* repeat labels.

* einsum support repeated labels.

* forward is ok for diagonal and undiagonalized.
TODO: check backward is ok by our theorem.

* backward is ok!

* fix by PR suggestions.

* fix ci error

* fix ci error

* fix ci warning

* [OpAttr]Adapt tensor axis for reduce_min/max/mean/sum/prod

* change logic for optimize

* modifty

* optimize the backward speed of EinsumOp

* add cache optimizer for einsum op

* EinsumOp: fix new dygraph mode error

* fix bug

* change Cache->InnerCache

* fix code

* fix

* add nan inf utils for einsum op

* add as_extra

* memory optimizer for einsum

* update code

* change einsum_v2 as default and add new flags: FLAG_einsum_opt=1|0

* make EInsumOP support bf16

* add unittest for BF16

* add condition for test_BF16

* fix bugs

* fix

* change logic for optimize

* modifty

* optimize the backward speed of EinsumOp

* add cache optimizer for einsum op

* EinsumOp: fix new dygraph mode error

* fix bug

* change Cache->InnerCache

* fix code

* fix

* add nan inf utils for einsum op

* add as_extra

* Compatible with v2.3 EinsumOp

* remove dispensable

* change logic for optimize

* modifty

* full api fix

* when out is None, go old dygraph mode

* by static check

* first version: support 2-inputs forwards. TODO: 1. backward  2. BroadCast  3. MultiVariable

* time out -> 120