* Change the api of DataParallel and Fleet (#29224)

* Add pure fp16 training with master weights. (#27712)

* add the weight decay func for the momentum op

* Add the multi_precision function in Momentum Optimizer.

* Make sure that the initial value of master weights are same with the fp16 weights.

* add static loss scaling.

* add the rescale_grad function in the pure fp16 training.

* use the original momentum updating method.

* Polish some codes, such as variable names.

* add docstring for apis.

* update the var creation details of _create_master_weight.

* not modify codes about imperative momentum updating.

* Fix the error of test_dist_sparse_tensor_load_momentum UT.

* add unit test for multi precision fp16 training.

* add more unit tests for CI.

* Use lower threshold values for allclose comparing in test_multi_precision_fp16_train UT.

* fix DATA_HOME path in win

Cherry-pick of PR #29226

fix nll_loss doc;test=document_fix

* add compile option WITH_TENSORRT

* add WITH_TENSORRT to ci paddle_buils.sh

* add WITH_TENSORRT to paddle_build.sh

* change FATAL to WARNING when TensorRT is not found and WITN_TENSORRT=ON, just to pass ci-py3 temporarily

* hot fix complle failed in gcc4.8

* fix failed unittest

* add lamb optimizer and unittest

* fix momentum resume training

* fix momentum acc

* add complex64 and complex128 type; add +-*/@ and slice opreator for complex types

* add test cases for complex elementwise, matmul and getitem unittest

* add test cases for complex types

* add test cases for complex matmul unittest

* fix fleet api doc

* The leaf tensor concept is exposed and the gradient accumulation of leaf tensor

* The leaf tensor concept is exposed and the gradient accumulation of leaf tensor

* fix coverage

* fix api doc

* fix CI unittest

* fix CI unittest

* fix unitest

* empty tensor does’t need inner_var_

* fix some error message

* fix en doc, test=document_fix

* add blank after code declare, test=document_fix

* refine doc of dropout, test=document_fix

* refine npair_loss and dropout, test=document_fix

- Make sure that oneDNN memory descriptors are created only once at
first iteration.

* lazy import for scipy

* rm unused check

* fix paramete prefetch & device guard
Co-authored-by: NMrChengmo <cmchengmo@163.com>
Co-authored-by: Nchengmo <chengmo@baidu.com>

* Add a class TensorInplaceVersion to count the inplace version and put it in framework::Tensor instead of Allocation or Variable.

* Add a new attribute `_inplace_version` for VarBase.

* Raise exception if an inplace operation can result in incorrect gradient computation.

* Add a new interface _bump_inplace_version() for VarBase to bump the version whenever the Tensor is modified through an inplace operation.

* For api assign, call _bump_inplace_version() when it's an inplace operation inn dynamic mode.

* Use original var_wrapper if the inplace_version is not changed.

* Replace SnapshotVarWrapperList with SnapshotVarWrapper to optimize performane.

* update, test=develop

As the title

* add musl docker build script

* rm space test=document_fix

* fix some docs and types errors test=document_fix

* move install of python requirement to docker build

* add copyright to docker file.

* add extr opts

* format docs

* add ut test add pip cache

* add more args description in readme

* add stack backtrace in ctest

* fix readme bugs

* test=develop, optimize async prefetch

* fix failed tests in yingchun gived list

* add unittests into static_mode_white_list

* add enable static

* fix dist unittest

* skip test_sigmoid_focal_loss_op & add gym

* revert no need skip unittests

* remove gym

* test=develop, rm pathlib