Example #1
0
func fast_skewexp(m mesh.Mesher) (g mesh.Mesher) {
	if r, c, _ := m.Size(); r != 3 && c != 1 {
		panic("fast_skewexp: Length of input mesh should be 3x1.")
	}

	g = mesh.Gen(nil, 3, 3)
	th := m.Norm(mesh.Two)
	if th != 0 {
		mscaled := mesh.Gen(nil, 3, 3)
		mscaled.Vec().Skew(m.Vec())
		mscaled.Scale(th)
		g.Sum(math.Sin(th), mscaled, mesh.I(3))
		mscaled.Powm(mscaled, 2)
		g.Sum(1-math.Cos(th), mscaled, g)
	} else {
		g = mesh.I(3)
	}
	return g
}
Example #2
0
func main() {
	sk := mesh.Gen(nil, 3, 3)
	w := mesh.Gen(vec.New(-1, 0, 0), 3, 1)
	sk.Vec().Skew(w.Vec())
	skexp := mesh.Gen(nil, 3, 3)
	st := time.Now()
	for i := 0; i < 1e3; i++ {
		skexp.Expm(sk)
	}
	fmt.Println("since: ", time.Since(st)/1e3)
	fmt.Println("skexp: ", skexp)

	st = time.Now()
	for i := 0; i < 1e3; i++ {
		skexp = fast_skewexp(w)
	}
	fmt.Println("since: ", time.Since(st)/1e3)
	fmt.Println("skexp: ", skexp)

}
Example #3
0
func NewTwist(w, q vec.Vectorer) Twister {
	t := new(twist)
	t.w = w // set the axis of motion of joint
	t.q = q // set the position a point on the axis of joint
	t.v = vec.Zeros(AxisLength)
	t.v.Cross(q, w) // qxw

	t.t = mesh.Gen(nil, TwistLength, 1)
	tvec := t.t.Vec().Slice()
	copy(tvec[3:], w.Slice())
	copy(tvec[:3], t.v.Slice())
	return t
}