ut3_entries_derivatives

t3toolbox.backend.ut3_sampling.ut3_entries_derivatives(index, pp, data, order)

def ut3_entries_derivatives(
        index: NDArray,                # int, shape=(d,)+W -- the grid points
        pp:    typ.Sequence[NDArray],  # perturbation vectors P, len=d, ith elm_shape=W+(Ni,)
        data:  UT3Data,
        order: int,                    # highest derivative order
) -> NDArray:                          # shape=(order+1,)+W+stack_shape

Symmetric entry derivatives of a uniform Tucker tensor train at index (shares sampling_derivatives.t3_entries_derivatives; the up-index jet slices Tucker fibers, so only pp is packed – index in [0,Ni) hits the real prefix).

Parameters:

• index (NDArray)

• pp (t3toolbox.backend.common.typ.Sequence[NDArray])

• data (UT3Data)

• order (int)

Return type:

NDArray