Matrix Operations and Finding Joint Angles

I am trying to find the angle between a segment and global y-axis.

HAT = icrest-hip;
UnitY = [0 1 0]

for  i = 1:size(position,1)

      normHAT(i,:) = HAT(i,:)/norm(HAT(i,:));

end

I created Y = zeros(171,3) which is the size of normHAT I want to put UnitY into each frame, i.e. 171 total.

Then I want to write a loop to find the angle at each frame

for i = 1:size(postion)
HATthetaY = acos(dot(Y(i,:),HAT))/(dot(Y(i,:),normHAT));

end

[bym]

perhaps some sample data for HAT would help

[Jan]

Do you have a question?