[MITOPENCOURSEWARE] 6.094 Introduction to Programming in MATLAB

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最新推荐文章于 2024-10-23 16:32:10 发布 · 1.2k 阅读

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#Matlab

这篇博客介绍了MATLAB的基础知识，包括变量、脚本、运算及数组操作。MATLAB被视作强大的图形计算器，同时具备编程语言功能。讲解了如何创建和修改变量、保存和加载变量到文件、注释脚本、使用内置命令如`help`和`doc`，以及数组的创建，如行向量、列向量和矩阵，还涉及到数组索引、指数和对数运算以及随机数生成。此外，提到了MATLAB的索引从0开始，并给出了 Homework 1 的相关提示，涉及科学技术法、虚数和统计计算。

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Introduction to MATLAB

Lecture 1 Variables, Scripts, and Operations

Matlab Basic
- MATLAB can be thought of as a super-powerful graphing calculator
- In addition it is a programming language
一些命令
- 帮助命令
  - help [ ]
  - doc [ ] 更详细的帮助
- 注释 %
  
  第一行注释为脚本的帮助文档
- 新建脚本 edit
  
  edit [ ].m
- 输出字符串disp
  
  注意字符串使用单引号
- 保存变量到文件中save
  
  save myFile a b
  - saves variables a and b to the file myfile.mat
  - myfile.mat file is saved in the current directory
- 移除当前环境中变量 clear
- 加载文件中变量load
- 清理命令窗口clc
变量
- 创建和修改的变量会一直保存在工作区
- Matlab is a weekly typed language. 不需要初始化变量
- 变量命名：首位必须是字母；以字母、数字、下划线_ 组成
- 大小写敏感
- Built-in variables. Don’t use these names!
  - i and j can be used to indicate complex numbers
  - pi has the value 3.1415926…
  - ans stores the last unassigned value (like on a calculator)
  - Inf and -Inf are positive and negative infinity
  - NaN represents ‘Not a Number’
若不想显示输出，则在句末加上;
数组[ ]

Two types of arrays
1. matrix of numbers (either double or complex)
2. cell array of objects (more advanced data structure)
- 行向量：在[ ] 中使用逗号或空格分隔值
- 列向量：在[ ]中使用;分隔
- size( )显示矩阵大小
- length( )得到矩阵长度
- Initialize a vector of ones, zeros, or random numbers
  » o=ones(1,10)
  row vector with 10 elements, all 1
  » z=zeros(23,1)
  column vector with 23 elements, all 0
  » r=rand(1,45)
  row vector with 45 elements (uniform [0,1])
  » n=nan(1,69)
  row vector of NaNs (useful for representing uninitialized variables)
- To initialize a linear vector of values use linspace
  » a=linspace(0,10,5)
  starts at 0, ends at 10 (inclusive), 5 values
  Can also use colon operator (:)
  » b=0:2:10
  starts at 0, increments by 2, and ends at or before 10
  increment can be decimal or negative
  » c=1:5
  if increment isn’t specified, default is 1
- To initialize logarithmically spaced values use logspace
  similar to linspace, but generate logarithmically spaced vectors
- Vector Indexing
  - Matlab 索引从0开始
  - The index argument can be a vector
  - 使用max和