load / save : all variables to a file load filename x -> loads x variable from the file to current context

end a line with semicolon (;) to prevent output to be shown in the output pane

every computation result is stored in ans variable

clear: removes all variables

everything is an array in MATLAB scalars are 1x1 arrays x = [3 4 5] is a row vector (1x3) x = [3; 4; 5] is a column vector (3x1)

how to create row vectors with evenly spaced elements x = start:spacing:end example: x = 1:2:9 gives x = [1 3 5 7 9]

linspace(start, end, #ofelements) -> row vector

how to create column vector from row vector? transpose: x = x’

how to create a matrix with random values, all zeros, all ones: rand(m, n) zeros(m, n) ones(m, n)

size(matrix) gives the size of a matrix as row vector that is of the form [#rows #columns]

INDEXING: matrix(i, j) where i is the row index and j is the column index

can also specify ranges using : like x(2:3)

end keyword can be used in indexing

when a single index is given to a matrix like x(idx) then matlab traverses column-by-column till idx is reached

05/03/2025

volumes = data(:, end-1:end) selscts the last two colums of data

for non consecutive indices use data([1 3 7])

Operations on arrays

+ adds a number to all elements of array + also adds two same sized arrays / divides each element of an array by a number max(vector), round(vector), sqrt(vector) perform element wise operation

* preforms matrix multiplication .* performs dot product

[1 2; 3 4; 5 6; 7 8] .* [1;2;3;4] is completely valid and gives dot product of both column vectors of array 1 with vector 2. result is: 1 2 6 8 15 18 28 32

Destructuring

[rows, columns] = size(matrix) creates 2 variables to store the two sizes

max() also returns two values when destructured like above, first one being the max value and second one being the index

if first variable needs to be ignored use ~ as [~, cols] = fn(vector)

randi([imin, imax], #rows, #cols) creates an array of specified size with values from uniformly distributed random integers between imin and imax

Plot

plot(x, y) plots same sized vectors also takes an optional third argument as a string defining formatting (color of line (r,g,b,c,m,y,k,w), line style (-,—,:,-.), marker shape (.,*,x,o,+,_,|))

hold on the next plot functions are drawn on the same graph

hold off continue in the default mode (separate graphs for each plot function)

plot(vector_x) plots the vector elements on the y axis with x axis having numbers 1 to n

other options like plot(x, y, “ro-”, LineWidth=4)

histogram(vector, FaceColor=“y”) plots a histogram in yellow color

Plot Annotations

title(“Plot title”) xlabel() and ylabel() for labelling the axes legend(“item1”, “item2”, “item3”, …) describe the plots in order of creation.

numbers can be joined in text using + operator

Importing

use the import tool the name of variable is the same as the filename access columns by filename.column_header

slicing also works here. generates a new table.

Relational operations

produce a logical output 1 (true) or 0 (false)

array also support logical operations, result is a new same-sized array with operation performed on each element example [1 2 3 4] < 3 gives [1 1 0 0]

Logical Indexing

we can use a logical array as an index. result is the original array but filtered accordingly example v1(v1 < 4) extracts all the elements of v1 that are less than 4

the arrays need not be the same

assignment can also be done as x(x==999) = 1

• we can combine logical and relational operators like
• x = v1(v1<6 & v1>5)

Decision branching

if-elseif-else

if condition block of code elseif condition2 block of code else block of code end

for loops

for loop_counter = vector block of code end

• length(vector) return the length of the vector

Summary

Summary of MATLAB Onramp

Basic Syntax

Desktop Management

Array Types

Evenly Spaced Vectors

Matrix Creation

Array Indexing

Array Operations

Multiple Outputs

Documentation

Plots

Tables

Logical Indexing

Programming