question about euclidean distance.

I want to find a function which can calculate the 3 dimension euclidean distance.

I have 9 arrays: Dx; Vx; ax; Dy; Vy; ay; Dz; Vz; az. the size of 9 arrays are the same.each array is 1*100000

the start point x0 =(Dx(1) Dy(1) Dz(1)) = (100 150 125)

How can I creat a function/script to run the following function:

x = Dx + Vx*t + 1/2*ax*t^2;

y = Dy + Vy*t + 1/2*ay*t^2;

z = Dz + Vz*t + 1/2*az*t^2;

t = 2; % it is fixed

L = ((x(n)-x(n-1))^2+(y(n)-y(n-1))^2+(z(n)-z(n-1))^2)^(1/2);

Thanks for your time and helping. :D

Answer 1

[Image Analyst]

This will do those equations:

function L = CalcDistance()
Dx = rand(1,100000);
Dy = rand(1,100000);
Dz = rand(1,100000);
Vx = rand(1,100000);
Vy = rand(1,100000);
Vz = rand(1,100000);
ax = rand(1,100000);
ay = rand(1,100000);
az = rand(1,100000);
t = 2; % it is fixed
x = Dx + Vx*t + 1/2*ax*t^2;
y = Dy + Vy*t + 1/2*ay*t^2;
z = Dz + Vz*t + 1/2*az*t^2;
dx = diff(x);
dy = diff(y);
dz = diff(z);
L = sqrt(dx.^2+ dy.^2+ dz.^2);

Of course you would not use rand(), you'd use the actual arrays, wherever you got them.

[Cheng Kang]

Thanks very much for your helping.

I have a further question, How can I set the starting point with this function, the start point is: x0 =(Dx(1) Dy(1) Dz(1)) = (100 150 125).

[Torsten]

How does the starting point come into play in the calculation of L ?

Best wishes

Torsten.

[Image Analyst]

You don't need x0. It's already in your D arrays at the first elements, so it's already taken into account in your L.

[Cheng Kang]

Thanks for your helping, my question is solved.

Have a nice day! :D

Kang