cherry-pick https://github.com/PaddlePaddle/book/tree/develop/paddle2.0_docs to docs/practices (PaddlePaddle#3694)

* image segmentation with u-net notebook (PaddlePaddle/book#870)

* image segmentation with u-net notebook

* update segmentation notebook

* imdb_bow_classification added (PaddlePaddle/book#871)

* dynamic graph example added (PaddlePaddle/book#876)

* cnn based image classification added, minor changes to dygraph example (PaddlePaddle/book#877)

* upgrade code that in image_segmentation from 2.0-alpha to 2.0-beta  (PaddlePaddle/book#879)

* image segmentation with u-net notebook

* update segmentation notebook

* upgrade code from 2.0-alpha to 2.0-beta

* add getting started doc (PaddlePaddle/book#880)

* image segmentation with u-net notebook

* update segmentation notebook

* upgrade code from 2.0-alpha to 2.0-beta

* add getting started doc

* delete invalid files

* add tow models with develop-paddle (PaddlePaddle/book#881)

* seq2seq with attention added (PaddlePaddle/book#882)

* seq2seq with attention added

* image_search use latest API

* update seq2seq with attention

* seq2seq with attention updated (PaddlePaddle/book#884)

* add linear_regression.ipynb (PaddlePaddle/book#885)

* fix_lenet_docs test=develop (PaddlePaddle/book#886)

* add high level api doc (PaddlePaddle/book#887)

* upgrade code to 2.0-beta

* add high level api doc

* fix_warning_info (PaddlePaddle/book#888)

* fix_test_loader (PaddlePaddle/book#889)

* fix_test_loader

* fix_mnist_wrongs

* update several notebooks  (PaddlePaddle/book#890)

* change from Pool2D to AdaptiveAvgPool2d in image_search

* hello paddle updated

* convnet_image_classification updated

* dynamic_graph updated

* convnet_image_classification updated

* imdb bow classification updated

* Fix style (PaddlePaddle/book#891)

* fix_some_wrongs

* fix_logs

* minor wording changes (PaddlePaddle/book#892)

* Course (PaddlePaddle/book#883)

* add save_model

* update api

* change api name

* change api name

* add define callback/metric/loss chapter (PaddlePaddle/book#893)

* upgrade code to 2.0-beta

* add high level api doc

* add define callback/metric/loss chapter

* add define callback/metric/loss chapter

* update several notebooks (PaddlePaddle/book#894)

* rerun code with 2.0-beta whl (PaddlePaddle/book#895)

* upgrade code to 2.0-beta

* add high level api doc

* add define callback/metric/loss chapter

* add define callback/metric/loss chapter

* rerun code with 2.0-beta whl

* fix lr (PaddlePaddle/book#896)

* fix docs for beta and change docs style (PaddlePaddle/book#900)

* change version from dev to 2.0Beta (PaddlePaddle/book#899)

* change version from dev to 2.0Beta

* change version

* fix linear_regression (PaddlePaddle/book#898)

* fix lr 9.12

* fix linear_regression

* Fix Bug: modify PetModel to PetNet (PaddlePaddle/book#901)

* upgrade code to 2.0-beta

* add high level api doc

* add define callback/metric/loss chapter

* add define callback/metric/loss chapter

* rerun code with 2.0-beta whl

* fix bug: modify PetModel to PetNet

* [Bug Fix]change paddle.disable_static() position (PaddlePaddle/book#902)

* upgrade code to 2.0-beta

* add high level api doc

* add define callback/metric/loss chapter

* add define callback/metric/loss chapter

* rerun code with 2.0-beta whl

* fix bug: modify PetModel to PetNet

* Fix BUG: change paddle.disable_static() position

* add addition_rnn doc (PaddlePaddle/book#916)

* Create addition_rnn.ipynb

Sequence to sequence learning for performing number addition

* fix some typo

fix some typo

* Update addition_rnn.ipynb

* 基于飞桨2.0的应用案例教程（通过AutoEncoder实现时序数据异常检测）代码提交 (PaddlePaddle/book#914)

* '提交数据文件'

* upload ipynb

* 对ipynbn修改

* 改用2.0 load 标题下署名，数据集文件删除

* 通过OCR实现验证码识别 代码提交 (PaddlePaddle/book#917)

* init OCR.ipynb

* 修改作者格式和一处描述

* 1. 更改pp为paddle。
2. 统一“预测”、“推理”术语为“预测”。
3. 简化文字部分描述。

* 添加super_resolution_sub_pixel (PaddlePaddle/book#910)

* 添加super_resolution_sub_pixel

* 添加super_resolution_sub_pixel

* 修改错别字等

* 添加作者信息

* update codes to use 2.0RC (PaddlePaddle/book#921)

* upgrade some code from 2.0-beta to 2.0-rc (PaddlePaddle/book#922)

* 基于飞桨2.0的关键点检测方法及应用之（人脸关键点检测）代码提交 (PaddlePaddle/book#919)

* upload facial_landmark.ipynb to landmark_detection

* upgrade code in facial_landmark.ipynb

* reviewed modify in facial_landmark.ipynb

* fix guides (PaddlePaddle/book#925)

* update save_model to 2.0rc (PaddlePaddle/book#924)

* update save_model to 2.0rc

* update save_model to 2.0rc

* udpate to reflect 2.0RC version numbers (PaddlePaddle/book#926)

* update to rc (PaddlePaddle/book#928)

* update to rc (PaddlePaddle/book#929)

* fix bugs (PaddlePaddle/book#930)

* update hapi and image_segmentation (PaddlePaddle/book#931)

* OCR案例更新 (PaddlePaddle/book#927)

* 根据最新反馈建议新增了以下修改：
1.添加数据集压缩包下载链接和使用方法
2.测试pillow在paddlepaddle安装后是否需要单独安装
3.在目录下添加测试数据
4.更换第三方解码器并实现青春版，待2.0更新ctc-decode后再更新该处代码。

* 适配2.0RC0

* Update the paddle version to 2.0.0-rc0 (PaddlePaddle/book#932)

Update the paddle version to 2.0.0-rc0

* update to rc (PaddlePaddle/book#933)

* update to rc1 (PaddlePaddle/book#940)

* update to rc1

* remote doc

* update lr to 2.0rc1 (PaddlePaddle/book#941)

* correct convnet iamge classify example (PaddlePaddle/book#942)

* 基于飞桨2.0的应用案例教程（通过DCGAN实现人脸图像生成）代码提交 (PaddlePaddle/book#923)

* Create dcgan_face.ipynb

通过DCGAN实现人脸图像生成

* 进一步改进格式

* 改为paddle.nn

* bug修复

* 更新生成器G和判别器D迭代图

* Update dcgan_face.ipynb

根据修改意见，进行文档改进

* 二次修改

根据修改意见进行第二次修改

* 进一步修改

根据修改意见第三次修改

* 12-11修改

根据修改意见再一次修改

* update to rc1 (PaddlePaddle/book#944)

* update to rc1

* update to rc1

* fix some bugs (PaddlePaddle/book#945)

* fix some bugs

* fix some bugs

* fix some bugs

* update images (PaddlePaddle/book#946)

* 基于飞桨2.0的应用案例教程（通过CycleGAN实现图像风格迁移）代码提交 (PaddlePaddle/book#938)

* add CycleGAN folder

* delete CycleGAN folder

* add CycleGAN floder

* add CycleGAN.ipynb

* delete other files

* move the CycleGAN folder

* add cyclegan.ipynb

* replace cyclegan.ipynb

* replace cyclegan.ipynb

* replace cyclegan.ipynb

* replace cyclegan.ipynb

* update cyclegan.ipynb

* Signed-off-by: ctkindle <18931518930@163.com>

* Signed-off-by: ctkindle <18931518930@163.com>

* Signed-off-by: ctkindle <18931518930@163.com>

* use min() instead of expression

* use min() instead of expression

* update to 2.0 (PaddlePaddle/book#948)

* update to 2.0

* fix typo bugs

* update to 2.0 (PaddlePaddle/book#949)

* update to 2.0

* update OCR

* update ocr

* 点云分类PointNet文档 (PaddlePaddle/book#958)

* 点云分类PointNet

* Update pointnet.ipynb

* Update pointnet.ipynb

* 使用协同过滤实现电影推荐 (PaddlePaddle/book#960)

* Add files via upload

* Delete Collaborative filtering.ipynb

* Create ttes.py

* Delete ttes.py

* Create test.py

* Add files via upload

* Delete test.py

* Add files via upload

* Delete Collaborative filtering.ipynb

* 飞桨2.0实例教程——使用预训练词向量 (PaddlePaddle/book#934)

* 飞桨2.0实例教程——使用预训练词向量

* 飞桨2.0实例教程——使用预训练词向量

删除了1312-1315行多余代码，训练和评测verbose改为1并重新生成了输出。

* Delete pretrained_word_embeddings.ipynb

* 飞桨2.0应用案例——使用预训练的词向量

删除了原先的位置，增加了预训练词向量文件夹

* Update pretrained_word_embeddings.ipynb

修改了两处说明（Line9,190），修改了最近修改时间（Line15）

* modified based on the latest comments

* 强化学习——Actor Critic Method (PaddlePaddle/book#961)

* Create Actor_Critic_Method.ipynb

* Update Actor_Critic_Method.ipynb

* Update Actor_Critic_Method.ipynb

* Update Actor_Critic_Method.ipynb

* Update Actor_Critic_Method.ipynb

* Update Actor_Critic_Method.ipynb

* Update Actor_Critic_Method.ipynb

* update to 2.0.1 (PaddlePaddle/book#962)

* update to 2.0.1

* fix index

* fix bugs (PaddlePaddle/book#969)

* update_to_2.1 (PaddlePaddle/book#977)

* update_to_2.1

* update practice

* update practice

* Advantage Actor-Critic(A2C) (PaddlePaddle/book#973)

* Create Advantage Actor-Critic(A2C).ipynb

* Update Advantage Actor-Critic(A2C).ipynb

* Update Advantage Actor-Critic(A2C).ipynb

* Update Advantage Actor-Critic(A2C).ipynb

* Update Advantage Actor-Critic(A2C).ipynb

* Deep_Deterministic_Policy_Gradient_(DDPG) (PaddlePaddle/book#967)

* Create  Deep_Deterministic_Policy_Gradient_(DDPG).ipynb

* Update Deep_Deterministic_Policy_Gradient_(DDPG).ipynb

* Update Deep_Deterministic_Policy_Gradient_(DDPG).ipynb

* Update Deep_Deterministic_Policy_Gradient_(DDPG).ipynb

* Update Deep_Deterministic_Policy_Gradient_(DDPG).ipynb

* Update Deep_Deterministic_Policy_Gradient_(DDPG).ipynb

* Update Deep_Deterministic_Policy_Gradient_(DDPG).ipynb

* Update Deep_Deterministic_Policy_Gradient_(DDPG).ipynb

* Update Deep_Deterministic_Policy_Gradient_(DDPG).ipynb

* rename it as docs/practices

Co-authored-by: Chunyu Zhang <saxon.zh@gmail.com>
Co-authored-by: jzhang533 <jzhang533@gmail.com>
Co-authored-by: Chen Long <1300851984@qq.com>
Co-authored-by: swtkiwi <1208425345@qq.com>
Co-authored-by: Chen Long <chenlong21@baidu.com>
Co-authored-by: dingjiaweiww <327396238@qq.com>
Co-authored-by: jm12138 <2286040843@qq.com>
Co-authored-by: Reatris <1521736513@qq.com>
Co-authored-by: GT-Zhang <46156734+GT-ZhangAcer@users.noreply.github.com>
Co-authored-by: Ralph LU <50762307+ralph0813@users.noreply.github.com>
Co-authored-by: zzs95 <zzs95@qq.com>
Co-authored-by: ZMpursue <39124862+ZMpursue@users.noreply.github.com>
Co-authored-by: FutureSI <52576338+ctkindle@users.noreply.github.com>
Co-authored-by: Zhihao Cao <1564758299@qq.com>
Co-authored-by: HUANGCHENGAI <36952116+HUANGCHENGAI@users.noreply.github.com>
Co-authored-by: WinSun <35953131+fiyen@users.noreply.github.com>
Co-authored-by: EastSmith <67545545+EastSmith@users.noreply.github.com>

Author: 17 people

.gitignore

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