Merge pull request !420 from amongo/FixMixedPrecisionForConstParam

clean clang format errors and cpplint errors

add some test cases for histogram summary operator

Merge pull request !435 from anthonyaje/fix_serdes_dataset

Merge pull request !400 from amongo/FixMathOps

Merge pull request !333 from jiangzhiwen/dataset/skip

Merge pull request !434 from h.farahat/multi_itr_bug

Add new test cases

format code

remove test case for fp64

add back scalar manipulation

remove save graph

fix pylint

Merge pull request !402 from yangzhenzhang/square

Merge pull request !383 from zhaozhenlong/cell/psnr

Merge pull request !286 from wangqiuliang/resolve-pynative-operator-issue

Merge pull request !183 from JunhanHu/cpp_sampler

Merge pull request !386 from changzherui/modify-ut

Merge pull request !343 from amongo/FixGradUsingInterfaceExtend

Merge pull request !217 from zhangbuxue/support_pow_operator

Merge pull request !379 from JichenZhao/groupnorm

add test case for grad concat

fix usage in test framework

fix testcase

format code

Merge pull request !304 from Xiaoda/modify-not-fully-use-devices-and-strategy-checking

Merge pull request !243 from h.farahat/nested_repeat

Merge pull request !294 from zhaozhenlong/cell/ssim

Merge pull request !312 from xiefangqi/xfq_apply_branch

Merge pull request !273 from liyong126/mindrecord_subset_sampler_python

Merge pull request !250 from casgj/gaojing_new4

Merge pull request !239 from fanglei/master

adjust internal api

Merge pull request !245 from chentingting/add_bool_type_check_in_comm_op