Learning MATLAB with Phil Parisi
Introduction to MATLAB
- MATLAB is a widely used programming language and software suite in academia and industry.
- Used for data analysis, scientific computing, and visualizations.
MATLAB Environment
MATLAB IDE
- Integrated Development Environment (IDE) for MATLAB.
- Command Window: Acts as a calculator for quick computations.
Basic Commands
- Arithmetic operations: e.g.,
7 + 8
, 10 - 5
.
sqrt()
: Function to calculate the square root.
- Variables:
ans
: Default variable for storing the last output.
- Creating variables: e.g.,
x = 10
, y = 20
.
- Clear variables:
clearvars
, clear command window: clc
.
Data Types and Variables
Creating Variables
- Assign values:
x = 10
, y = 20
.
- Workspace: Displays current variables and their values.
- Types of Variables:
- Double: Default numeric type.
- Char: Character strings (use single quotes).
- String: Use double quotes.
Suppressing Output
- Use semicolons
;
to suppress output in the command window.
- Comma Operator: Allows multiple commands on one line.
MATLAB Functions and Commands
- Whos: Lists current variables and their types.
- Linspace: Generates linearly spaced vectors.
- Example:
linspace(0, 100, 20)
: From 0 to 100 with 20 points.
- Ones and Zeros: Generate matrices filled with 1s or 0s.
- Identity Matrix:
eye(n)
generates an n x n identity matrix.
Matrices and Arrays
Creating Arrays and Matrices
- Define manually with brackets
[]
, e.g., [1 2 3]
.
- Operations: Addition, subtraction, multiplication follow matrix rules.
- Transpose:
'
operator for transposing matrices.
Element-wise Operations
- Use the dot
.
before operators for element-wise operations.
- Example:
x.^2
for squaring each element of x
.
Indexing and Manipulating Data
- Access elements by indices:
a(2,3)
for 2nd row, 3rd column.
- Use colon
:
to access entire rows or columns.
- End keyword: Represents the last index.
Plotting in MATLAB
Basic Plotting
- Plot function:
plot(x, y)
creates a graph.
- Customization: Colors, markers, and line styles.
- Example:
plot(x, y, 'r--')
for red dashed lines.
- Titles and Labels: Use
xlabel
, ylabel
, title
for axes and titles.
Multiple Plots
- Hold on: Overlay multiple plots on the same graph.
- Figure Windows:
figure(n)
for separate plot windows.
- Subplots: Display multiple plots in a single figure using
subplot
.
Logical Operations and Control Flow
Logical Tests
- Perform logical tests:
x > 5
, x == 3
.
- Output is a logical array of 1s (true) and 0s (false).
If Statements
- Basic syntax:
if condition, actions, end
.
- Used to execute code based on conditions.
Loops
For Loops
- Syntax:
for variable = range, actions, end
.
- Used for iterating over a sequence of numbers.
While Loops
- Syntax:
while condition, actions, end
.
- Loop continues as long as condition is true.
Custom Functions
- Creating Functions: Use
function
keyword.
- Input/Output arguments: Define in the function header.
- Save function in a separate
.m
file in the same directory.
Optimization and Performance
- Vectorization: Process data in vectors for efficiency.
- Timing Code: Use
tic
and toc
to measure code execution time.
Conclusion
- MATLAB offers extensive capabilities for data manipulation and visualization.
- Encouraged to explore MATLAB documentation and online resources for further learning.
Note: This is a comprehensive overview intended to give a foundational understanding of MATLAB basics.