* fix for log xxx

* add int32/int64 for cpu/gpu; add float16/bfloat16 for cpu forward

* fix docstring

* fix bug

* fix bugs

* fix bugs

* fix bugs

* fix bugs

* fix bug

* using cast

* fix test

* fix api

* fix other bugs

* fix ci bug for not using dygraph guard

* add bfloat16 test

* fix ut

* bf16

* exp/expm1 support int32/int64

* fix ut

* fix ut

* fix ut