A 6x6 covariance matrix, backed by an Nx tensor.
Used to express uncertainty over 6-DOF pose or twist estimates (3 translation + 3 rotation, or 3 linear + 3 angular). The matrix is mathematically expected to be symmetric and positive semi-definite; this module does not enforce those invariants on construction.
Follows the same typed-Nx-wrapper pattern as BB.Math.Covariance3.
Examples
iex> c = BB.Math.Covariance6.diagonal([0.01, 0.01, 0.01, 0.001, 0.001, 0.001])
iex> BB.Math.Covariance6.get(c, 3, 3)
0.001Summary
Functions
Builds a diagonal covariance from a list of six variances or a {6}
tensor.
Wraps an existing {6, 6} tensor. Convenience alias for new/1.
Reads a scalar element at row/column (i, j).
Returns the 6x6 identity matrix as a covariance.
Creates a covariance from a {6, 6} tensor.
Returns the underlying tensor.
Returns the zero covariance.
Types
@type t() :: %BB.Math.Covariance6{tensor: Nx.Tensor.t()}
Functions
@spec diagonal([number()] | Nx.Tensor.t()) :: t()
Builds a diagonal covariance from a list of six variances or a {6}
tensor.
Examples
iex> c = BB.Math.Covariance6.diagonal([1.0, 2.0, 3.0, 4.0, 5.0, 6.0])
iex> BB.Math.Covariance6.get(c, 5, 5)
6.0@spec from_tensor(Nx.Tensor.t()) :: t()
Wraps an existing {6, 6} tensor. Convenience alias for new/1.
Reads a scalar element at row/column (i, j).
@spec identity() :: t()
Returns the 6x6 identity matrix as a covariance.
Examples
iex> c = BB.Math.Covariance6.identity()
iex> {BB.Math.Covariance6.get(c, 0, 0), BB.Math.Covariance6.get(c, 0, 1)}
{1.0, 0.0}@spec new(Nx.Tensor.t()) :: t()
Creates a covariance from a {6, 6} tensor.
@spec to_tensor(t()) :: Nx.Tensor.t()
Returns the underlying tensor.
@spec zero() :: t()
Returns the zero covariance.
Examples
iex> c = BB.Math.Covariance6.zero()
iex> BB.Math.Covariance6.get(c, 0, 0)
0.0