Function collapse_pseudobulk 

pub fn collapse_pseudobulk(
    data_vec: SparseIoVec,
    annotations: &CellAnnotations,
    membership: &CellTypeMembership,
    a0: f32,
    b0: f32,
) -> Result<CollapsedPseudobulk>

Collapse single-cell counts into Poisson-Gamma pseudobulk parameters.

Groups cells by individual, then weights each cell’s expression by its cell type membership (hard one-hot or soft probabilities).

Arguments

• data_vec - Sparse single-cell count matrix (SparseIoVec over one or more backends)
• annotations - Cell-to-individual mapping
• membership - Membership matrix (cells × cell_types) and cell type names
• a0 - Gamma prior shape parameter (default: 1.0)
• b0 - Gamma prior rate parameter (default: 1.0)