assemble_z

t3toolbox.backend.probing.assemble_z(tucker_cores, etas)

def assemble_z(
        tucker_cores:   typ.Union[typ.Sequence[NDArray], NDArray],  # len=d. elm_shape=C+(ni,Ni)
        etas:           typ.Union[typ.Sequence[NDArray], NDArray],  # len=d. elm_shape=W+C+(ni,)
) -> typ.Union[typ.Sequence[NDArray], NDArray]: # zs. len=d, elm_shape=W+C+(Ni,)

Assemble probes from downward edge variables.

See Section 6.2, particularly Figure 7 and Algorithm 5, in:

Alger, N., Christierson, B., Chen, P., & Ghattas, O. (2026). “Tucker Tensor Train Taylor Series.” arXiv preprint arXiv:2603.21141. https://arxiv.org/abs/2603.21141

Parameters:

• tucker_cores (t3toolbox.backend.common.typ.Union[t3toolbox.backend.common.typ.Sequence[NDArray], NDArray])

• etas (t3toolbox.backend.common.typ.Union[t3toolbox.backend.common.typ.Sequence[NDArray], NDArray])

Return type:

t3toolbox.backend.common.typ.Union[t3toolbox.backend.common.typ.Sequence[NDArray], NDArray]