How do I calculate the angle between a vector and a matrix directly in MATLAB 7.13 (R2011b)?

I have a vector 'v' which is 3x1 in dimension and a matrix 'A' which is 3Xn in dimension where 'n' is any large number > 1.

Answer 1

[MathWorks Support Team]

Currently there is no way to directly compute the angle between a vector and a matrix.

Calculating the angle between vectors involves computing the dot product and dividing by the norm of both the participating vectors. The existing NORM functionality does not operate individually on columns of a matrix.

Please find the function NORMCOL attached below, which can be used to compute the norm of a matrix along columns. Using NORMCOL one can compute the angle as follows:

To find the angle in degrees, you may run the following command on the matrix A (3 X n columns) and vector v (3 X 1 single column):

Angles = acos((v'*A)./(norm(v).*normcol(A)))*(180/pi)