Rotating a Vector

Hello! I am wondering if anyone has an elegant way to rotate a vector by a specified degree.

For example, I have a vector that goes from (0,0) to (-1,-12). I want to rotate this vector by 5 degrees, incrementally until it reaches the x-axis.

Obviously this can be done from the math, but I wonder if anyone has a nicer way of doing this.

Thank you in advance!

Amina

Answer 1

[Andrei Bobrov]

complex

vR = v*[1;1i]*exp(-1i*theta*pi/180)

[A]

Very nice, thanks!

The only problem that I am having is using vR as it is a 1x1 element and therefore not in usual vector form. Is there a way that I can mash this into that form?

[James Tursa]

real(vR) are the x components of the vectors, and imag(vR) are the y components of the vectors.

Answer 2

[Sean de Wolski]

Unless I'm missing something just use the rotation matrix:

v = [-1 -12];
theta = 5;
R = [cosd(theta) -sind(theta); sind(theta) cosd(theta)];

vR = v*R;

quiver(0,0,v(1),v(2))
hold on
quiver(0,0,vR(1),vR(2))

[A]

This works great! Thank you :)

Answer 3

[Sayyed Ahmad Khadem]

Hi all,

I read this blog, and I have similar problem. I would be thankful to kindly give me some clues if you know.

Suppose that we have a vector field in y-x plane, let's consider following example:

Vector Field : Vf = [u, v]

u=x

v=y

Now, I need to revolve the given vector field around the center of plot (i.e. [0 0]). Does anyone can provide some nice solution?

Thanks in advance,

[Adam Danz]

You can use quiverRotate() from the file exchange.

You can flip the direction of the quiver arrows by using the quiver handle or by flipping the vector component prior to producing the quiver plot.

h = quiver(x,y,u,v); 
quiverRotate(h)

% or 

[Ur,Vr] = quiverRotate(u,v); 
quiver(x,y,Ur,Vr)

Answer 4

[wenhao li]

Have you solved this problem? I met this problem, too.

[Sayyed Ahmad Khadem]

Hi Wenhao,

No one has suggested a viable approach yet ! :-( I am still struggling !