Array operations

• An example of a row vector

  >> a=[1 2 3]
  
  a =
  
       1     2     3
  

• An example of a column vector

  >> a=[1;2;3]
  
  a =
  
     1
     2
     3
  

• If you need to multiply, square, divide, etc. any array you need to proceed the operation by a '.'.

  >> n=0:5
  
  n =
  
       0     1     2     3     4     5
  
  >> n^2
  ??? Error using = > ^
  Matrix must be square.
  
  >> n.^2
  
  ans =
  
        0     1     4     9    16    25
  

• Be careful when multiplying two arrays.

  >> a=[1 2 3]
  
  a =
  
       1     2     3
  
  >> b=[4;5;6]
  
  b =
  
       4
       5
       6
  
  >> a*b
  
  ans =
  
      32
  
  
  >> a'.*b
  
  ans =
  
       4
       10
       18
  

  Since a is a row vector and b is a column vector, if you use a*b you will have performed a dot product. On the other had if you want to multiply every element in a by every element in b to generate a new vector, then you need to transpose one of the two vectors by using ' and then multiply the two vectors using .*.