@spec bent_chain(keyword()) :: Nx.Tensor.t()

Generate points for a chain with bends at each joint.

Each joint bends in the XY plane (around Z axis) by the specified angle. Angles are cumulative - each segment's direction is the previous direction plus the bend angle.

Options

• :lengths - list of segment lengths (required)
• :angles - list of bend angles in radians, one per segment (required)

          First angle is absolute direction from origin,
          subsequent angles are relative bends.

• :start - starting point (default: {0, 0, 0})

Example

# Straight arm then 90° elbow bend
iex> bent_chain(lengths: [0.3, 0.2], angles: [0.0, :math.pi/2])
# Points at: {0,0,0}, {0.3,0,0}, {0.3,0.2,0}

@spec collapsed(non_neg_integer(), {number(), number(), number()}) :: Nx.Tensor.t()

Generate points that are all at the same location (degenerate case).

Useful for testing edge cases where direction vectors have zero length.

@spec elbow_bend(keyword()) :: Nx.Tensor.t()

Generate a chain that's straight for the first segment, then bends.

Convenience function for the common case of testing elbow-like joints.

Options

• :lengths - list of segment lengths (required)
• :bend_at - index of joint where bend occurs (0-indexed, default: 1)
• :bend_angle - angle of bend in radians (required)

Example

iex> elbow_bend(lengths: [0.3, 0.2], bend_angle: :math.pi/2)
# Straight along X, then bent 90° at elbow

@spec points([{number(), number(), number()}]) :: Nx.Tensor.t()

Convert a list of {x, y, z} tuples to an Nx tensor.

Example

iex> points([{0, 0, 0}, {1, 0, 0}, {2, 0, 0}])
#Nx.Tensor<f64[3][3]>

@spec rotate(Nx.Tensor.t(), number(), :x | :y | :z) :: Nx.Tensor.t()

Rotate all points around an axis passing through the origin.

Parameters

• points - Nx tensor of shape {n, 3}
• angle - rotation angle in radians
• axis - :x, :y, or :z

Example

iex> straight_chain(lengths: [1.0]) |> rotate(:math.pi/2, :z)
# Rotates from +X to +Y direction

@spec straight_chain(keyword()) :: Nx.Tensor.t()

Generate points for a straight chain along the +X axis starting at origin.

Options

• :lengths - list of segment lengths (required)
• :start - starting point (default: {0, 0, 0})

Example

iex> straight_chain(lengths: [0.3, 0.2])
# Points at: {0,0,0}, {0.3,0,0}, {0.5,0,0}