Function solve_batch 

pub fn solve_batch(
    accounts: &[BatchAccount],
    settings: Option<SolverSettings>,
) -> Vec<AccountResult> 

Solves every account’s rolling sequence, in parallel over the account axis when the rayon cargo feature is enabled (roadmap 3.2).

Each account gets its own workspace (equilibration and factorizations built once per account, warm starts chained across its dates), so the batch does the same numerical work as calling solve_sequence per account — results are bit-identical to that loop regardless of the feature or thread count. One entry is returned per account, in input order; a failed account never affects the others.