Useful Matrices Generators

1. MATLAB
Developed by
Pranoti R. Doke
Date:
1
Chapter 5
(Useful Matrices Generators )

2. Useful Matrices Generators :
2
Zeros a matrix filled with zeros
ones a matrix filled with ones
rand a matrix with uniformly distributed random elements
randn a matrix with normally distributed random elements
eye identity matrix
>> a = zeros(2,3)
a =0 0 0
0 0 0
>> b = ones(2,2)/2
b =
0.5000 0.5000
0.5000 0.5000
>> u = rand(1,5)
u =
0.9218 0.7382 0.1763 0.4057 0.9355

3. 1/7 …
3
>> n = randn(5,5)
n =
-0.4326 1.1909 -0.1867 0.1139 0.2944
-1.6656 1.1892 0.7258 1.0668 -1.3362
0.1253 -0.0376 -0.5883 0.0593 0.7143
0.2877 0.3273 2.1832 -0.0956 1.6236
-1.1465 0.1746 -0.1364 -0.8323 -0.6918
>> eye(3)
ans
1 0 0
0 1 0
0 0 1

4. 2/7 …
4
>> a = [1 2 3 ; 4 5 6 ; 7 8 9]
a =1 2 3
4 5 6
7 8 9
>> a(3 , 2)
ans = 8
>> a(2 , :)
ans = 4 5 6
>> a(:,3)
ans = 3
6
9

5. 3/7 …
5
(ref.Basics of Matlab and Beyond)
>> a = [1 2 3 ; 4 5 6 ; 7 8 9]
a =
1 2 3
4 5 6
7 8 9
>> a(: , : , 2) = a*2
a(: , : , 1) =
1 2 3
4 5 6
7 8 9
a(: , : , 2) =
2 4 6
8 10 12
14 16 18
>> a (: , : ,3) = eye(3)
a(: , : , 3) =
1 0 0
0 1 0
0 0 1

6. Examples to solve :
6
Q). Create 3*3 ones matrix
Q). Create 4*4 zeros matrix
Q). Calculate rand and randn
Q). Show 4*4 identity matrix using MATLAB command