UniformCorewiseGeometry.frame

t3toolbox.uniform_manifold.UniformCorewiseGeometry.frame(x)

def frame(
        self,
        x:  ut3.UniformTuckerTensorTrain,
) -> ubv.UT3Frame:  # the (U, G, G, G) non-orthonormal frame at x

The core-parameter frame at x: (U, G, G, G) (down/left/right all the TT supercore G).

The mask analog of the cores: up = down = tucker_edge_mask (the U-G Tucker edges) and left = right = tt_edge_mask (the G-G TT bonds, full length d+1) – the Section 6.3 substitution (P, Q, O) -> G gives all three non-up slots the single core G’s rank structure, with no boundary slicing (the [:-1] / [1:] gauge shift is a variations, not a frame, thing).

Parameters:

x (UniformTuckerTensorTrain)

Return type:

UT3Frame