Merge pull request !4247 from 章一智/channel_swap_op

Merge pull request !3850 from islam_amin/randomaffine_op

Merge pull request !4250 from anthonyaje/fix_cpp_api_iterator

Merge pull request !3917 from luoyang/c-api

Merge pull request !3979 from MahdiRahmaniHanzaki/mixup

Merge pull request !4192 from xiefangqi/xfq_validate_ci

Merge pull request !4068 from yangzhenzhang/add-concat-op

Merge pull request !3982 from peixu_ren/custom_pp_ops

split into datasets

review fix

fix merge issues

fixed minddata lite build issues

Merge pull request !3346 from lixiachen/repeat_rework

Merge pull request !3944 from xiefangqi/md_new_api_CelebA

Merge pull request !4072 from hewei/fixbug_tensor_equal

Merge pull request !4060 from fary86/fix_while_concat_specialize_error

1. Check if data_ is null before compare it;
2. Always allocate an array for data_ even if size is zero.

Merge pull request !4019 from yao_yf/add_layout_in_stra_ckpt

Merge pull request !4005 from fangzehua/unsortedsegsum

Merge pull request !4004 from fangzehua/squaresumall

Merge pull request !3789 from riemann_penn/eager_mode_sparse

Merge pull request !3977 from nhussain/multi_dim_concat_2

Merge pull request !3860 from xiefangqi/md_new_api_cocodataset

Merge pull request !3983 from huanghui/reduce-min-fission-pass

Merge pull request !4000 from zhangbuxue/improve_bool_for_tensor

Merge pull request !3966 from lichen/add_dropout_distributed_op

Merge pull request !3938 from liubuyu/master

Merge pull request !3807 from 徐永飞/master