T3FrameWeights.from_t3weights

classmethod t3toolbox.frame_variations_format.T3FrameWeights.from_t3weights(t3_weights)

def from_t3weights(cls, t3_weights: 't3.T3Weights') -> 'T3FrameWeights':

Build a tangent metric from base-point edge weights (e.g. T3Weights.from_t3svd(x)): up = down = tucker_weights, left = tt_weights[:-1], right = tt_weights[1:]. The TT slicing follows the Hᵢ bond convention (Hᵢ’s left bond is TT bond i, right bond i+1) – simple but convention-dependent, hence a named method. The result pairs with a minimal-rank tangent at x (where the complement rank nD equals the Tucker rank nU, as for t3svd output); the Grasedyck–Kramer metric is T3FrameWeights.from_t3weights(T3Weights.from_t3svd(x)).reciprocal().

Parameters:

t3_weights (T3Weights)

Return type:

T3FrameWeights