Install Anaconda & Jupyter Notebook

0. Intro

Anaconda offers the easiest way to perform Python/R data science and machine learning on a single machine.

Jupyter Notebook is the original web application for creating and sharing computational documents.

More information related to this topic could be found from:Installing Python · cs109/content Wiki · GitHub

1. Install Anaconda

官网下载链接:Anaconda | Anaconda Distribution

For Windows user:

  1. 点击绿色按钮即可下载,若下载速度过慢,可以考虑镜像清华大学开源软件镜像站 | Tsinghua Open Source Mirror,或右键使用迅雷下载。
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  2. 下载完毕后打开安装包,一路next默认同意即可。安装进度条走完需要约五到六分钟。

  3. 安装成功后,打开开始菜单(win+s)→搜索Anaconda,打开。
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  4. 一般首次启动时间较长,有时会提示更新,安装更新即可。

  5. 启动 Jupyter Notebookd31359c5234f7109b9819b59c01f0f46.png

  6. 正常情况下浏览器打开,可以看到所在目录

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  7. .ipynb文件添加到该目录下,点击即可在浏览器中打开。

Install Libraries

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Change the working directory

如果未生成过 Jupyter 的配置文件jupyter_notebook_config.py
打开 Anaconda Prompt
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输入

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jupyter notebook --generate-config

配置文件生成在了对应路径下,即C:\Users\xiaonan\.jupyter

打开此配置文件,找到c.NotebookApp.notebook_dir字段,等号右边填入需要变更为的目标路径
c.NotebookApp.notebook_dir = "D:\XJTLU\INT303\Labs",并去除行前的注释#

重新打开Jupyter Notebook 即可。

微信开发者工具 版本管理 Azure Repo

通过ssh连接

生成ssh密钥
Windows Platform:
win+r键调出“运行”
输入cmd调出命令行
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输入
ssh-keygen -t rsa -C "xiaonan.pan"
-t rsa 表示采用 rsa 算法
-C “xiaonan.pan” 表示注释
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键入 密钥保存的路径(一般照抄即可)

在给定的文件夹C:\Users\xiaon.ssh下,我们看到
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id_rsa.pub即为公钥内容
选择记事本打开之
复制其中所有的内容,填写到GitHub的Key中
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单击Add SSH key

Ubuntu Platform:
在终端输入
ssh-keygen -t rsa -C "xiaonan.pan"
后续步骤如上。

.ssh保存在 ~/.ssh/下
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利用
vim id_rsa.pub 
打开复制公钥,上传
在使用 git 命令行时注意使用SSH连接:
git clone git@ssh.dev.azure.com:v3/CPT202-GroupA-8/Maplus/Maplus

id_rsa 即为 rsa私钥,须保密保存
id_rsa 即为 rsa公钥,上传到Azure SSH key 管理页面

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右下角确认add

随后配置微信开发者工具的版本管理
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设置

网络和认证改为
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密码口令是刚刚 ssh生产中 passphase 的内容,此处我并没有设置passphase,故留空。

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配置远程代码仓库

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URL填入SSH地址
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配置完成。

Memory Management

为什么要有逻辑地址的概念?
程序是给定的,硬件可用的地址是变化的。
所以需要引入逻辑地址的概念,做逻辑地址与物理地址的映射。

如何映射?

固定偏移量映射
缺陷:

  1. 一个进程使用的最大内存量是变化的。
  2. 分配的内存的利用效率不高,内碎片
  3. 外碎片

分页
程序逻辑内存分为多个页(page)
物理内存分为多个帧(page frame)
一个内存地址处存储的内容 为一个字节, 1B
利用页表(Page Table) 存储二者的对应关系
页号,帧号,当前这一条目是否可用,读写权限,脏….
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页表每个进程都需要维护

内存的一个地址里面是一个字节(Byte)的数据
32位操作系统物理地址有2^32个,因而只能使用4GB的内存。
任何一个32位的内存可操作的逻辑地址是2^32个即4GB。
上条势必会造成多个程序使用的总内存和大于物理内存,此时会借助磁盘,将不着急用的内存先放进磁盘,页表中显示的是磁盘。

内存映射的过程。

32位系统,256MB内存,页大小为4KB(有四千条地址)
32位程序
4KB = 2^12 bit

也就是说,1个页中提供12位偏移
逻辑地址 32bit = 20bit页号(32-12)bit + 12bit偏移
物理地址 28bit = 16(28-16)bit,即16bit帧号 + 12bit偏移

分页过程中,需要两次读内存时间上有待优化,页表占用空间较大空间上也有待优化(先读内存中的页表,再去拿到对应的地址)

分页中的时间与空间优化。
TLB快标,将最长访问的8-128个页表项存到访问速度更快的硬件中,一般是在MMU中(集成在CPU中)

内存管理-分段 segment 段号+页号
段仅仅保留了逻辑上的意义。
进程间通信-共享内存方式

Cpu的cache如何起作用:

CPU接收到指令后,它会最先向CPU中的一级缓存(L1 Cache)去寻找相关的数据,然一级缓存是与CPU同频运行的,但是由于容量较小,所以不可能每次都命中。这时CPU会继续向下一级的二级缓存(L2 Cache)寻找,同样的道理,当所需要的数据在二级缓存中也没有的话,会继续转向L3 Cache、内存(主存)和硬盘.

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Using Git

Intro

The git directory acts as a database for all the changes tracked in Git and the working tree acts as a sandbox where we can edit the current version of the files

Staging Area(index)

A  file maintained by Git that contains all of the information about what files and changes are going to go into your next commit

Any Git project will consist of 3 sections: Git directory, working tree, Staging area

After modifying a file, we need to stage those changes and then commit them afterwards

chmod +x all_check.py //makes the scripts excutable

A commit message is required, or the commit will be aborted

which command would we use to view pending changes?
git status 

to generate a patch to fix the current bug
diff fix_permission.py fix_permissions_modified.py > fix_permission.patch

apply the patch to the file:
patch fix_names.conf < fix_names.patch 

the wdiff commandhighlights the words that changed in a file instead of working by line

A commit is a collection of edits which has been submitted to the version control system for safe keeping

Within a VCS, project files are organized in centralized locations called repositories where they can be called upon later

Git 常见命令

git add will add a file to the staging area and mark it for tracking

git log will give us information about the author of each commit, its timestamp, and each commit message

git config -l is used to check the current user configuration

git status is used to retrieve information about changes waiting to be committed

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user@ubuntu: ~$ git config --global user.email "me@example.com"
user@ubuntu: ~$ git config --global user.name "My name"

Workflow

init git:

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user@ubuntu: ~$ mkdir checks
user@ubuntu: ~$ cd checks
user@ubuntu: ~/checks$ git init
Initialized empty Git repository in /home/user/checks/.git/

The area outside the git directory is the working tree. The working tree is the current version of your project.

add git

-m to pass the commit message
user@ubuntu: ~/checks$ git commit -m 'Add periods to the end of sentences.'

anatomy of a  Commit Message

  • short summary
  • detailed explaation
  • more infomation related to the message

git log :
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git log -p 

git commit -a 
A shortcut to stage any changes to tracked files and commit them in one step
git commit -a dosen’t work on new files

Can only write short message

user@ubuntu:~/scripts$ git commit -a -m "Call check_reboot from main, exit with 1 on error"

for truely small changes

Git uses the HEAD alias to represent the currently checked-out snapshot of your project.

This lets you know what the contents of your working directory should be.

user@ubuntu:~/scripts$ git add -p

#when using -p flag, git will show us the change being added and ask us if we want to stage it or not

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user@ubuntu:~/scripts$ git diff #only unstaged changes by default

user@ubuntu:~/scripts$ git diff -staged #to see the changes that are staged but not committed

we can see the actual stage changes before we call git commit

You can remove files from your repository with the git rm command, which will stop the file from being tracked by git and remove it from the git directory

git checkout
followed by the name of the file you want to revert.

git reset

We’ve added something to the staging area that we didn’t actually want to commit, we can unstage our changes by using git reset.

git add
end up adding any change done in the working tree to the staing area

--amend
git commit --amend
overwirte the previous commit

Avoid amending commits that have already been made public

With git revert, a new commit is created with inverse changes. This cancels previous changes instead of making it as though the original commit never happened.

You can verify the data you get back out is the exact same data you put in

git show

help us easily view the log message and diff output the last commit if we don’t know the commit ID

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git show hashcommitid
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git revert hashcommitid
user@ubuntu:~/scripts$ git revert 30e70