MATLAB: Dot product of matrix with scalar

Question

This is a trivial question.

I have a matrix

B = [1 1 1; 5 5 5; 9 9 9; 2 2 2; 6 6 6; 10 10 10; 3 3 3; 7 7 7; 11 11 11; 4 4 4; 8 8 8; 12 12 12];
n = [1,1,1]

How can I find the dot product of each row of B with n?

I know I can use for loops and do this for all rows of B:

 row1 = dot(B(i,:),n);

But there should be a better method using indexing……right? Using for loops isn't efficient.

Answer 1

Hi,

multiplying each row with a vector is nothing else but the matrix vector multiplication:

B*n'

(n' since your n is a row vector).

Titus