symforce.geo.unsupported.pose2_se2 module

class Pose2_SE2(R=None, t=None)[source]

Bases: Pose2

Group of two-dimensional rigid body transformations - SE(2).

There is no generated runtime analogue of this class in the sym package, which means you cannot use it as an input or output of generated functions or as a variable in an optimized Values. This is intentional - in general, you should use the Pose2 class instead of this one, because the generated expressions will be significantly more efficient. If you are sure that you need the different behavior of this class, it’s here for reference or for use in symbolic expressions.

The storage space is a complex (real, imag) for rotation followed by a position (x, y).

The tangent space is one angle for rotation followed by two elements for translation in the rotated frame. This means we interpolate the translation in the tangent of the rotating frame for lie operations. This can be useful but is more expensive than SO(2) x R2 for often no benefit.

Parameters:

  • R (T.Optional[Rot2]) –

  • t (T.Optional[Vector2]) –

classmethod from_tangent(v, epsilon=0.0)[source]

Mapping from the tangent space vector about identity into a group element.

Parameters:
Return type:

Pose2_SE2

to_tangent(epsilon=0.0)[source]

Mapping from this element to the tangent space vector about identity.

Parameters:

epsilon (float) –

Return type:

List[float]

storage_D_tangent()[source]

Note: generated from symforce/notebooks/storage_D_tangent.ipynb

Return type:

Matrix

tangent_D_storage()[source]

Note: generated from symforce/notebooks/tangent_D_storage.ipynb

Return type:

Matrix

retract(vec, epsilon=0.0)[source]

Applies a tangent space perturbation vec to self. Often used in optimization to update nonlinear values from an update step in the tangent space.

Implementation is simply compose(self, from_tangent(vec)). Conceptually represents self + vec if self is a vector.

Parameters:
Return type:

Pose2_SE2

local_coordinates(b, epsilon=0.0)[source]

Computes a tangent space perturbation around self to produce b. Often used in optimization to minimize the distance between two group elements.

Implementation is simply to_tangent(between(self, b)). Tangent space perturbation that conceptually represents b - self if self is a vector.

Parameters:
Return type:

List[float]

classmethod hat(vec)[source]
Parameters:

vec (List[float]) –

Return type:

Matrix33