What is vectorization? Why use vectorization instead of loops?

Over at Reddit, a user asked about vectorization vs. a loop. This is a fundemental concept in MATLAB. So, what is vectorization? Why use it instead of loops?

Answer 1

[Hans Scharler]

Vectorization is about replacing explicit loops with matrix and vector operations. This can lead to more readable and efficient code. MATLAB is particularly well-suited for vectorized operations as it is designed to work with matrices and vectors natively.

Here's a normal loop approach to square each element in a vector.

n = 10;
vector = 1:n;

result = zeros(1, n);

% Use a loop to square each element of a vector
for i = 1:n
    result(i) = vector(i)^2;
end

disp(result);

     1     4     9    16    25    36    49    64    81   100

Here's how this looks with vectorization:

vector = 1:10;

% Square each element of a vector using vectorization
result = vector.^2;

disp(result);

     1     4     9    16    25    36    49    64    81   100

The magic here is the ".^" which is an element-wise operation. You can also do this with ".*" and "./".

Docs: https://www.mathworks.com/help/matlab/ref/power.html