Getting started on Matlab

Running Matlab

To run Matlab on your own computer, follow the instructions of the official website. No worries though if you don't have a Matlab license at hand. You can:

• either run it on one of Stanford's computers (e.g. in libraries)
• or connect remotely to the University's computing environment.

In the latter case, here is the procedure:

1. Open a terminal window (Terminal on Mac/Linux and PuTTY or equivalent on Windows)
2. Access the cluster via the command:

ssh your-sunetid@rice.stanford.edu

1. Enter your SUNet password and choose your favorite 2FA method when prompted
2. Run Matlab with the commands:

module load matlab
matlab

This is it, you are now ready to use Matlab!

Getting started

Basic operations

Here are the basic operations you can perform.

You have to be careful about the way you combine multiple operations one after another. Formulas are evaluated from left to right, and exponentiation has priority over multiplication and division, which have priority over addition and subtraction.

Also, use = to assign a value to a variable.

Built-in functions

Trigonometry

Here are some useful functions to tackle problems involving angles:

Exponentials and square root

The following functions are often used:

Rounding and remainder

The following functions can be useful:

Vectors

Syntax

To define a vector, use square brackets [ ] and use either spaces or commas to separate the elements.

• Row vector: To define a row vector, type:

v = [1 2 3]

• Column vector: To define a column vector, you can either use the transpose operator ' on a row vector or separate the elements with semicolons ;:

v = [1 2 3]'
v = [1; 2; 3]

Quick generation

For vectors with a high number of elements, you can use the following commands:

Common operations

By noting v and w two vectors and k a constant, here are common operations:

Matrices

Syntax

To define a matrix, use square brackets [ ] and use semicolons ; to separate the rows.

A = [1 2 3; 4 5 6; 7 8 9]

Quick generation

The following commands are often used:

Common operations

By noting A and B two matrices and k a constant, here are common operations:

Writing your functions

To write your own function, you have to create a new .m file with the name of your function.

Simple case

If your function has one output y and one input x, the file my_function.m should look like this:

function y = my_function(x)
    y = x^2;
end

Advanced case

If your function has multiple outputs [y1, y2] and multiple inputs (x1, x2), the file my_function.m should look like this:

function [y1, y2] = my_function(x1, x2)
    y1 = x1 + x2;
    y2 = x1 * x2;
end

Mathematical operators

Logical operators

The following operators can be used to perform logical operations:

Relational operators

The following operators can be used to compare two values:

Matlab operators

Loops

The following operators can be used to perform loops:

• For loop:

for i = 1:10
    disp(i)
end

• While loop:

i = 1;
while i <= 10
    disp(i)
    i = i + 1;
end

Statements

The following operators can be used to perform statements:

• If statement:

if x > 0
    disp('Positive')
elseif x < 0
    disp('Negative')
else
    disp('Zero')
end

Plots

Single plot

To plot a single vector y against x, use:

plot(x, y)
xlabel('x')
ylabel('y')
title('My plot')

Multiple plots

To plot multiple vectors in the same figure, use hold on:

plot(x, y1)
hold on
plot(x, y2)
legend('y1', 'y2')

Saving plots

To save a plot, use saveas:

saveas(gcf, 'my_plot.png')

Good practices

Extra tips

• Use % to write comments in your code.
• Use ; at the end of a line to suppress the output in the command window.
• Use clc to clear the command window.
• Use clear all to clear all variables from the workspace.
• Use close all to close all open figures.
• Use help function_name to get help about a specific function.