# DP¶

class menpofit.differentiable.DP[source]

Bases: object

Object that is able to take its own derivative with respect to the parametrisation.

The parametrisation of objects is typically defined by the menpo.base.Vectorizable interface. As a result, DP is a mix-in that should be inherited along with menpo.base.Vectorizable.

abstract d_dp(points)[source]

The derivative of this spatial object with respect to the parametrisation changes evaluated at points.

Parameters

points ((n_points, n_dims) ndarray) – The spatial points at which the derivative should be evaluated.

Returns

d_dp ((n_points, n_parameters, n_dims) ndarray) – The Jacobian with respect to the parametrisation.

d_dp[i, j, k] is the scalar differential change that the k’th dimension of the i’th point experiences due to a first order change in the j’th scalar in the parametrisation vector.