spd_learn.functional.exp_map_pcm#

spd_learn.functional.exp_map_pcm(V: Tensor, P: Tensor | None = None, theta: float = 0.5, eps: float = 1e-06) → Tensor[source]#

Compute Riemannian exponential map under the Power-Cholesky Metric.

Parameters:
  • V (torch.Tensor) – Tangent matrix / deformed coordinates of shape (…, n, n).

  • P (torch.Tensor, optional) – Base SPD matrix of shape (…, n, n). If None, identity \(I\) is used.

  • theta (float, default=0.5) – Power parameter (\(\theta \neq 0\)).

  • eps (float, default=1e-6) – Numerical threshold to clamp diagonal.

Returns:

Reconstructed SPD matrix of shape (…, n, n).

Return type:

torch.Tensor