Basic Commands

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|| Sarvam Krishna Arpanam ||

Sl. No

Operator or Function Purpose

1 a = 5 Define a scalar without semi colon operator

2 b = 10; Define a scalar with a semi colon operator

3 c = a + b Basic addition operator

4 who Shows the variables in the workspace

5 whos Information about the variables in the workspace

6 clc Clearing the command window

7 clear all Clearing the workspace

8 A = [2 5 6 7] Defining a row vector 9 B = [9 11 14 15]; Defining a row vector with semicolon operator

10 C = A + B Vector addition; Try subtraction

11 D = B' Transpose of a vector

12 Multi = A*D Multiplication of two vectors

13 Multi_new = A.*B Multiplying each element of A with each element of B

14 div_new = A.\B Multiplying each element of A by each element of B

15 powA = A.^5 Every element of A is raised to the power of 5

16 greatest = max(A) Maximum of a vector; Try min(A) for minimum 17 tot = sum(A) Sum totaling the elements of a vector; try prod(A) 18 averageA = mean(A) Determining the mean of vector A; try median(A) and

mode(A) 19 std(A) Determining the standard deviation of A; try var(A) for

variance.

20 length(A) Determines the length of a vecotr 21 A = [2 3 4; 9 10 11; 17 8 19]

B = [8 9 0; 7 12 13; 21 45 6] Defining square matrices

22 A(2,3) Accessing the element at 2nd row and third column of A 23 A(:,2) Accessing all rows, 2nd column 24 A(1,:) Accessing, 1st row, all columns

Basic Commands

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25 C = A + B Addition of matrices; Try subtraction & multiplication

26 Cprod = A*B Product of two matrices

27 Element_prod = A.*B Dot Product

28 det(A) Gives the determinant of A 29 inv(A) Inverse of A 30 rank(A) Gives the rank of A 31 [m,n] = size(A) Determines the size of A matrix 32 eig(A) Determines the eigen values of A 33 eigvec(A) Determines the eigen vector of A 34 cond(A) Determines the condition number of A 35 input Enables user input

36 elfun Displays the elementary functions

37 abs(x), cos(x), exp(x), log(x),log10(x), cosh(x), sin(x), tan(x), sqrt(x), tanh(x)

Some of the built-in functions

38 4e4 Scientific form of 40000

39 pi, Inf, NaN, -Inf Inbuilt constants

40 display('Hello') Displays the string inside the quote. In this case, it displays Hello

41 mod(100,3) Displays Modulus after division 42 rand(5) Use of rand function to generate random numbers 43 randint(5) Use of randint function to generate random integers 44 randint(5,3,[291 108]) Randomly generate integers from a given range 45 D = zeros(5,3) Generate a matrix of zeros 46 E = ones(5,8) Generate a matrix of ones 47 eye(7) Generate an identity matrix of size 7 48 X = linspace(50,80,1000) Generate 1000 uniformly spaced points between 50 and

80

49 N = 7:18 Create elements from 7 to 18 with an interval of 1

50 N = 2: 0.5 : 5 Create elements from 2 to 5 with an interval of 0.5

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51 ceil(3.1) Gives the ceil of a number 52 floor(4.95) Gives the floor of a number 53 round(6.45) Rounds the number to the nearest integer 54 A = randint(3,3,[10 100]);

C= diag(A) Extract the diagonal elements of A matrix

55 trace(A) Sum of the diagonal elements of A matrix 56 sum(diag(A)) Summing the diagonal elements of A matrix 57 max(A,[],1) Finds the maximum number in each column of A 58 max(A,[],2) Finds the maximum number in each row of A 59 A = 3+5i; Defining a single complex number with colon operator

60 B = 9+67i Defining a single complex number without colon operator

61 C = A+ B Addition of two complex numbers; try subtraction; Define matrices of complex numbers and multipy

62 tic MATLAB starts a stopwatch timer

63 toc MATLAB stops a stopwatch timer

64 save test Saves all the variables in the workspace to a MAT file titled test.MAT

65 save filename X Saves only the variable X in a MAT file titled filename

66 load test Loads all the variables in the file titled test.MAT to the workspace

67 what Shows the list of MATLAB specific files

68 dir Lists the contents of the current directory

69 pwd Shows the current directory

70 X = 1:10; Y = X.^2 plot(X,Y,'r*')

Plots a graph between the values of X and Y;

71 xlabel('Values of X') Adding label on the x-axis 72 ylabel('Values of Y') Adding label on the y-axis 73 title('Variation of X with Y') Adding a title to the plot 74 text(X(5),Y(5),'Central Adding a string on the plot at a specified point

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Piont') 75 axis([4 8 10 40]) Plots the graph in between x = 4 to 8 and y = 10 to 40 76 grid Places grid on the plot

77 figure Creates a new figure (or plot) 78 plot(X,Y) Plots a graph between the X and Y values 79 close all Closes all the figure window

80 loglog Helps in the plotting of log log graph; Look into

semilogx and semilogy

81 X = 1:10; Y = X.^2;Z = X.^3

plot3(X,Y,Z) Plots a three dimensional plot with continuous line

82 hold on Preserves the contents of the current plot while plotting something new

83 clf Clears current figure

84 lookfor Helps to find help on a keyword (slow) 85 help Helps to find help on an existing command (fast) 86 demo Launches the demo window

87 str1 = 'Hi'

Str2 = 'How are you'

Defining strings

88 strvcat(str1,Str2) Does a vertical concatenation 89 strcat(str1,Str2) Does a horizontal concatenation 90 %This will not hurt Commenting

91 Recall previous lines 92 Recall next line 93 Mission = ['Will I be'...

'winning here'...

'or whining'];

Shows how a single command can be broken across multiple lines

94 a = [1 2 3;4 5 6;7 8 9] b = [a 10*a;-a [1 0 0;0 1 0;0 0 1]]

Shows concatenating of matrices

95 sort(x) Sort the elements of x in ascending order 96 unique(x) Extracts only the unique elements of x

Basic Commands

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