Operations on Lie groupsΒΆ

manif supports the following operations with Lie groups,

Operation

Code

Base Operation

Inverse

\(\bf\mathcal{X}^{-1}\)

X.inverse()

Composition

\(\bf\mathcal{X}\circ\bf\mathcal{Y}\)

X * Y
X.compose(Y)

Hat

\(\boldsymbol\varphi^\wedge\)

w.hat()

Act on vector

\(\bf\mathcal{X}\circ{\bf v}\)

X.act(v)

Retract to group element

\(\exp(\boldsymbol\varphi^\wedge)\)

w.exp()

Lift to tangent space

\(\log(\bf\mathcal{X})^\vee\)

X.log()

Manifold Adjoint

\(\mathrm{Adj}(\bf\mathcal{X})\)

X.adj()

Tangent adjoint

\(\mathrm{adj}(\boldsymbol\varphi^\wedge)\)

w.smallAdj()

Composed Operation

Manifold right plus

\({\bf\mathcal{X}}\circ\exp(\boldsymbol\varphi^\wedge)\)

X + w
X.plus(w)
X.rplus(w)

Manifold left plus

\(\exp(\boldsymbol\varphi^\wedge)\circ\bf\mathcal{X}\)

w + X
w.plus(X)
w.lplus(X)

Manifold right minus

\(\log(\bf\mathcal{Y}^{-1}\circ\bf\mathcal{X})^\vee\)

X - Y
X.minus(Y)
X.rminus(Y)

Manifold left minus

\(\log(\bf\mathcal{X}\circ\bf\mathcal{Y}^{-1})^\vee\)

X.lminus(Y)

Between

\({\bf\mathcal{X}^{-1}}\circ{\bf\mathcal{Y}}\)

X.between(Y)

Inner Product

\(\langle\boldsymbol\varphi,\boldsymbol\tau\rangle\)

w.inner(t)

Norm

\(\left\lVert\boldsymbol\varphi\right\rVert\)

w.weightedNorm()
w.squaredWeightedNorm()

Above, \({\bf\mathcal{X}}\) & \({\bf\mathcal{Y}}\) (X & Y) represent group elements, \({\boldsymbol\varphi^\wedge}\) & \({\boldsymbol\tau^\wedge}\) represent elements in the Lie algebra of the Lie group, \({\boldsymbol\varphi}\) & \({\boldsymbol\tau}\) (w & t) represent the same elements of the tangent space but expressed in Cartesian coordinates in \(\mathbb{R}^n\), and \(\mathbf{v}\) (v) represents any element of \(\mathbb{R}^n\).