ut3_to_t3

t3toolbox.backend.ut3_conversions.ut3_to_t3(x)

def ut3_to_t3(
        x: typ.Tuple[
            NDArray,                          # tucker_supercore
            NDArray,                          # tt_supercore
            typ.Tuple[int, ...],              # shape, static int tuple
            typ.Tuple[NDArray, NDArray],      # (tucker_edge_mask, tt_edge_mask)
        ],
) -> typ.Union[
    typ.Tuple[typ.Tuple[NDArray, ...], typ.Tuple[NDArray, ...]],  # (tucker_cores, tt_cores), if unstacked
    typ.Tuple,                                                     # else a nested tree (shape stack_shape) of those
]:

Convert uniform supercores + masks back to ragged TuckerTensorTrain core pairs.

Unstacked: returns one (tucker_cores, tt_cores). Stacked: returns a nested tuple (shaped like stack_shape) of such pairs – a tree, since a varying-rank stack has no single stacked TuckerTensorTrain (docs/uniform_ranks_and_varieties.md). The real sub-blocks are selected through the rank masks (boolean indexing, ascending order) rather than by slicing a prefix, since an edge mask may be gappy after +/x (docs/uniform_masks_vs_ranks.md).

Parameters:

x (t3toolbox.backend.common.typ.Tuple[NDArray, NDArray, t3toolbox.backend.common.typ.Tuple[int, Ellipsis], t3toolbox.backend.common.typ.Tuple[NDArray, NDArray]])

Return type:

t3toolbox.backend.common.typ.Union[t3toolbox.backend.common.typ.Tuple[t3toolbox.backend.common.typ.Tuple[NDArray, Ellipsis], t3toolbox.backend.common.typ.Tuple[NDArray, Ellipsis]], t3toolbox.backend.common.typ.Tuple]