[Machine Learning] Octave Basic Operations

You can do baisc math:

5+6
32-8
1/2
2^3
1 == 2 % ans = 0 means false
1 ~=1 % 1 not equals to 2. ans = 1 means true
1 && 0
1 || 0
xor(1, 0)

 

Change the output:

PS1('>> ')

 

Semicolon: 

If you don't use semicolon, it prints the output, if you add semicolon, it doesn't print output:

 

disp(a): print value:

a=pi;
disp(sprintf('2 decimals: %0.2f', a)) # 2 decimals: 3.14

 

Format:

 

 

Matrix / Vector:

 

Step increasment:

v = 1:0.2:2 # a row vector start from 1, each element increase by 0.2 until 2

 

if step is 1:

v = 1:6 # from 1 to 6

 

2by3 matrix with all 1:

ones(2,3)

"""
ans =

   1   1   1
   1   1   1

"""

c = 2*ones(2,3)
"""

c =

   2   2   2

   2   2   2

"""

w = zeros(1,3) 
w= rand(3,3) # uniform distribution between zero and one.
w = randn(3,3) # Gaussian distribution with mean zero and variance or standard deviation equal to one

 

More complex matrix:

w = -6 + sqrt(10)*(randn(1, 10000));
hist(w)
hist(w, 50)