Error using * Inner matrix dimensions must agree urgent help please.

I got this prompt and I dont know how to solve it.

function water_vec=water_light_ray_vec(air_vec,refractive_index)
normal_vec=[0 
            0 
            1];
%   normal_vec=[0;0;1];

water_vec=(air_vec-normal_vec*(air_vec*normal_vec-sqrt(air_vec*normal_vec-1+refractive_index^2)))/refractive_index ;

end

refractive index size is 1.33 1 by 1

normal_vec is [0

0

1]

air_vec is [-0.173230940506992

-0.116707951859014

0.667867059147687]

help will be very appreciated.

[Stephen23]

@Or Peer: you need to learn the differernce between array and matrix operations:

https://www.mathworks.com/help/matlab/matlab_prog/array-vs-matrix-operations.html

Answer 1

[Geoff Hayes]

Or - the error is due to the following multiplciation

air_vec*normal_vec

where both arrays/vectors are 3x1 and so the error message makes sense. What do you want to be doing here? Multiplying the two to get a scalar or do you want to keep the 3x1 dimensions?

[Or Peer]

I would like to keep the 3x1 dimensions, thank you for the help.

[Geoff Hayes]

try

air_vec .* normal_vec

which is element-wise multiplication.