MATRIX OPERATIONS

Deleting row or column in matrix:

An empty braces [] will define the entire row and column of a matrix is deleted. Let us consider an example deleting 2^nd row of the:

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

a ( 2 , : ) = []

if we want to delete the 3^rd  column of the given example

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

a(: , 3)=[]

Matrix Operation:

Now let us discuss some commonly used matrix operations are:

Addition and subtraction of matrix:

While performing matrix addition and subtraction when both the operand of matrices must have same number of rows and columns.

Let us consider an example

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

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

c = a + b

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

b = [2 1 3; 3 2 1; 4 5 6];

d = a – b

If we run script file we get:

c= 6 6 9

     5 7 9

     14 16 18

d= 1 1 1

     1 3 5

      3 3 3

Division of (right, left) matrix:

If we want to perform the division of two matrices left (\) or right (/) division operation, when both the operand of matrices must have same number of rows and columns.

Now let us consider an example:

a = [1 2 3; 4 2 6; 7 5 2];

 b = [3 5 6; 2 3 8; 5 7 2];

 c = a / b

d = a \ b

If we run the above example we get output as:

c = -0.7916   0.1666   0.2083

      1.0833   4.3333   0.9166

       2.9583 4.6666   3.8333

 d =

-3.27778   -1.05556   -4.86111

 -0.11111   0.11111   -0.27778

 3.05556      1.27778   4.30556

Transpose of matrix:

The transpose operation will be defined as switching of the rows and columns in a matrix. And it will be represented as a single quote (‘).

Let us consider example:

a = [11 12 13; 14 8 6; 27 8 9]

b = a’

It displayed has:

a = 11 12 13

      14 8   6

      27 8   9

b = 11 14 27

       12 8   8 

       13 6   9