def compute_kinetic(vel, mass):
    """Computes the kinetic energy of the system

    Args:
        vel -- np.array(N,dim) containing all the particle velocities
        mass -- value of particle mass

    Returns:
        -- kinetic energy of the system

    Notes:
        -- the routine runs using Numba @njit decorator for faster run time
    """
    k = 0

    for i in range(vel.shape[0]):
        k += vel[i, 0]*vel[i, 0]
        k += vel[i, 1]*vel[i, 1]
        k += vel[i, 2]*vel[i, 2]

    return k*mass/2