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Matrix Calculations in COMMAND window
Write nos. from 1 to 10 >> H=1:10
Let M=[1 2; 3 4] and N=[4 5 ;6 7],
Matrix Multiplication >> R=M*N
Element wise multiplication >> S=M.*N
Let A=[4 5 6] and B=[7 8 9] i.e. two vectors
Dot product is given by, >> C=dot(A,B)
Cross Product is given by, >> D=cross(A,B)
Create 4*4 identity matix >> eye(4)
3*2 matrix, all elements are 1 >> ones(3,2)
3*2 matrix, all elements are 0 >> zeros(3,2)
Operations Write these in COMMAND window
Define matrix >> A=[1 2 3;4 5 6; 7 8 9]
Transpose of A >>B=A'
All elements of 2nd column of matrix A >> C=A(:,2)
All elements of 2nd row of matrix A >> D=A(2,:)
Size of matrix A >> E=size(A)
1st & 2nd row and 2nd & 3rd column >> F=A(1:2,2:3)
Extract A13 element of matrix A >> G=A(1,3)](https://image.slidesharecdn.com/basicsofmatlabprogramming-190927123322/85/Basics-of-MATLAB-programming-4-320.jpg)
![clear all;
clc;
m=input('Enter the row size of array:m ')
n=input('Enter the column size of array:n ')
a=[m;n] % a is Matrix of size a(m*n)
disp('Enter the elements of matrix :a ')
for i=1:m
for j=1:n
a(i,j)=input('') % if a=2*3 matrix ,then a11 a12 a13 then a21 a22 a23
end
end
disp(a)
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Write this programme as a ‘SCRIPT’ file and save with ‘.m’ extension
Enter ‘F5’ to run the programme
Define 2D array (Matrix of m*n)](https://image.slidesharecdn.com/basicsofmatlabprogramming-190927123322/85/Basics-of-MATLAB-programming-6-320.jpg)
Basics of MATLAB programming
- 1. Basic Guidelines for MATLAB Programming By RANJAN PAL Ph.D. Research Scholar IIT Kharagpur 1
- 2. 2 MATLAB window (1) Directory where you save your files (2) Script file(3) Saved files in your current directory (4) MATLAB Workspace (5) Command window
- 3. Commonly used commands 3 Command Name Usage disp displays message in command window fprintf Prints the i/o msg in command window n takes you to next line t acts like a space bar clc clears command window clear all clears all the data stored in workspace %’some txt msg’ its for user information In the beginning of every code, when you define a function, remember that the name of function and the name that you save for .m file should be same
- 4. 4 Matrix Calculations in COMMAND window Write nos. from 1 to 10 >> H=1:10 Let M=[1 2; 3 4] and N=[4 5 ;6 7], Matrix Multiplication >> R=M*N Element wise multiplication >> S=M.*N Let A=[4 5 6] and B=[7 8 9] i.e. two vectors Dot product is given by, >> C=dot(A,B) Cross Product is given by, >> D=cross(A,B) Create 4*4 identity matix >> eye(4) 3*2 matrix, all elements are 1 >> ones(3,2) 3*2 matrix, all elements are 0 >> zeros(3,2) Operations Write these in COMMAND window Define matrix >> A=[1 2 3;4 5 6; 7 8 9] Transpose of A >>B=A' All elements of 2nd column of matrix A >> C=A(:,2) All elements of 2nd row of matrix A >> D=A(2,:) Size of matrix A >> E=size(A) 1st & 2nd row and 2nd & 3rd column >> F=A(1:2,2:3) Extract A13 element of matrix A >> G=A(1,3)
- 5. Define 1D array (Matrix of 1*n) clear all; clc; % No of rows by default is 1 i.e m=1 % matrix is of the form : a1j n=input('Enter the column size of array:n ') a=1:n % a is matrix of size : 1*n disp('Enter the elements of matrix:a ') for j=1:n a(1,j)=input('') % if a=1*n matrix ,then a11 a12 a13 ...........a 1n end 5 Write this programme as a ‘SCRIPT’ file and save with ‘.m’ extension Enter ‘F5’ to run the programme
- 6. clear all; clc; m=input('Enter the row size of array:m ') n=input('Enter the column size of array:n ') a=[m;n] % a is Matrix of size a(m*n) disp('Enter the elements of matrix :a ') for i=1:m for j=1:n a(i,j)=input('') % if a=2*3 matrix ,then a11 a12 a13 then a21 a22 a23 end end disp(a) 6 Write this programme as a ‘SCRIPT’ file and save with ‘.m’ extension Enter ‘F5’ to run the programme Define 2D array (Matrix of m*n)
- 7. Basics of function handlers • Lets say we have f=x+y, And we need to find f(4,5) • In matlab, to achieve this ,we make use of function handlers • In matlab command window, write this: >>f = @(x,y) (x+y); % Press enter >>F=f(4,5) % Press enter (*You get the desired value i.e. 9*) (*Observe what happens when you remove the (;) symbol *) 7
- 8. Obtaining the roots of Transcendental Eq by function handling ‘@(x)’ when you know approximately where the root lies We define a function as follows: >> f = @(x) cos(x) * cosh(x) + 1 ; % cos(x)*cosh(x)+1=0 >> fzero(f,2) ans = 1.8751 This is just to tell you that MATLAB has many inbuilt functions to solve a given problem like roots of equations, ode etc. You can explore them for you interest But not to be used in exams 8
- 9. Plot more than 1 curve: ‘Sub-Plot’ 9 Write this programme as a ‘SCRIPT’ file and save with ‘.m’ extension Enter ‘F5’ to run the programme
- 10. • Prepare this excel file that contains two sheets • Save this file with the name ‘Square Cube.xlsx’ 10 Read From Excel File - 1 Sheet 1 ‘Square’ Sheet 2: ‘cube’
- 11. Read From Excel File - 2 11 Write this programme as a ‘SCRIPT’ file and save with ‘.m’ extension Enter ‘F5’ to run the programme
- 13. PROBLEM SUM 13
- 14. Make your own function 14
- 15. GET INPUT VALUES FROM THE USER and CALL the user defined function 15
- 16. To run the programme, you can follow any one of the below mentioned steps: 1) press F5 in MATLAB editor, after you have saved the ‘Run_this_code.m’ file 2) click the ‘Run’ option in MATLAB editor Run the Programme 16
- 17. O/P of Euler Cauchy for ODE 17
- 18. Points to Remember • This PPT is to give you basic idea about MATLAB programming, it doesn't teach you MATLAB thoroughly. • You need to explore it more yourself. • You can take help of https://www.mathworks.com/ for syntax and learn new commands 18