pub fn concat_decoder_blocks(
blocks: &[ArrayView2<'_, f64>],
) -> Result<Array2<f64>, String>Expand description
Stack a list of per-atom decoder blocks (each shape (basis_size_k, P))
column-wise into a single Jacobian of shape (P, sum_k basis_size_k).
Used by the Python diagnostics dispatcher to feed
jacobian_sparsity_metrics from a ManifoldSAE.decoder_blocks payload
without doing the concatenation in Python.