# tfg.geometry.transformation.axis_angle.from_euler_with_small_angles_approximation

Converts small Euler angles to an axis-angle representation.

tfg.geometry.transformation.axis_angle.from_euler_with_small_angles_approximation(
angles,
name=None
)


Under the small angle assumption,

$$\sin(x)$$
and
$$\cos(x)$$
can be approximated by their second order Taylor expansions, where
$$\sin(x) \approx x$$
and
$$\cos(x) \approx 1 - \frac{x^2}{2}$$
. In the current implementation, the smallness of the angles is not verified.

#### Note:

The conversion is performed by first converting to a quaternion representation, and then by converting the quaternion to an axis-angle.

#### Note:

In the following, A1 to An are optional batch dimensions.

#### Args:

• angles: A tensor of shape [A1, ..., An, 3], where the last dimension represents the three small Euler angles. [A1, ..., An, 0] is the angle about x in radians [A1, ..., An, 1] is the angle about y in radians and [A1, ..., An, 2] is the angle about z in radians.
• name: A name for this op that defaults to "axis_angle_from_euler_with_small_angles_approximation".

#### Returns:

A tuple of two tensors, respectively of shape [A1, ..., An, 3] and [A1, ..., An, 1], where the first tensor represents the axis, and the second represents the angle. The resulting axis is a normalized vector.