Learn Matlab from Phil Parisi

Introduction

• Phil Parisi, a PhD engineering student, presents a crash course on Matlab.
• Matlab is a programming language and software suite used for data analysis, scientific computing, and visualizations, widely used in academia and industry.

The Matlab IDE

• IDE (Integrated Development Environment) is where all programming is done in Matlab.
• Command window: Serves as a powerful calculator.
  • Example commands: 7 + 8, sqrt(225).
• Workspace: Shows variables created during the session.
  • Example: After typing 7 + 8, variable ans holds value 15.
• Command window commands:
  • clc: Clears the command window.
  • clear vars: Clears workspace variables.
• Creating variables:
  • Example: x = 10, y = 20.
  • Variables can be manipulated: x + y.
  • Use semicolons ; to suppress output.
• Viewing variables: who and whos commands list current variables and their types.
• Variable types: double, char, string.
  • Examples of defining: w = 'new', z = "York".

Basic Operations and Punctuation

• Operators: +, -, *, /, ^ (power).
• Compound expressions: sqrt(8*9) same as x = 8*9; sqrt(x).
• Indexing:
  • Example: Accessing elements in arrays or matrices: a(2,3) gives element in 2nd row, 3rd column.
  • Using end to access the last element.*

Vectors and Matrices

• Creating vectors: x = 1:10, linspace(0, 100, 20).
• Defining matrices:
  • Example: A = [1 3; 2 -10].
• Matrix operations: A * B, A .* B (element-wise).
• Common matrix functions:
  • Zeros matrix: zeros(2,3).
  • Ones matrix: ones(2,3).
  • Identity matrix: eye(3).

Scripts and Functions

• Scripts: Run multiple lines of code. clearvars, clc commands suggested at the start.
• Creating Scripts: Use new script button.
• Running Scripts: Use the Run button or Ctrl+Enter for quick execution.
• Functions: Custom functions with input and output arguments.
• Anonymous functions: Quick functions for singular tasks.
• Example: y = @(x) -((x - 3).^2) + 10;.

Plotting

• Plotting functions: plot(x, y), plot(x, y, 'r--') for red dashed lines.
• Plot attributes: xlabel(), ylabel(), title(), legend().
• Multiple plots: hold on to overlay plots.
• Subplots: subplot(rows, columns, position) to create complex figures.
• Figure manipulation: figure, axes properties.

Logical and Conditional Statements

• Logical operations: >, <, ==, ~=, &&, ||.
• Conditional statements: if, else, elseif, end.
  • Example: if num3 >= 3, disp('wow'), end.

Loops

• For Loop: for index = start:step:end, ... end.
  • Example: for i = 1:10, disp(i), end.
• While Loop: while condition, ... end.
  • Example: while z > 2, z = z - 1, end.

Performance Comparison and Optimization

• Vectorized operations: Faster than loops for large datasets.
• Timing code: Use tic and toc to measure execution time.

Good Programming Practices

• Variable naming conventions: Use descriptive names, avoid Matlab reserved words.
• File naming: Start with a letter, include only valid characters.
• Comments: Use % for comments, %% for section titles.

Final Takeaways

• Matlab is versatile for a wide range of mathematical computations and visualizations.
• Practice with scripts, plots, and functions to become proficient.
• Explore Matlab’s extensive documentation for further learning.

Helpful Tips

• Use Matlab’s built-in help (help, doc) and online resources to learn and troubleshoot.
• Experiment with commands and scripts to understand their functions.
• Optimize code for performance, especially when handling large datasets.