Method Relinearize

src/txgraph.cpp:2157–2197

}

std::pair<uint64_t, bool> GenericClusterImpl::Relinearize(TxGraphImpl& graph, int level, uint64_t max_cost) noexcept
{
    // We can only relinearize Clusters that do not need splitting.
    Assume(!NeedsSplitting());
    // No work is required for Clusters which are already optimally linearized.
    if (IsOptimal()) return {0, false};
    // Invoke the actual linearization algorithm (passing in the existing one).
    uint64_t rng_seed = graph.m_rng.rand64();
    const auto fallback_order = [&](DepGraphIndex a, DepGraphIndex b) noexcept {
        const auto ref_a = graph.m_entries[m_mapping[a]].m_ref;
        const auto ref_b = graph.m_entries[m_mapping[b]].m_ref;
        return graph.m_fallback_order(*ref_a, *ref_b);
    };
    auto [linearization, optimal, cost] = Linearize(
        /*depgraph=*/m_depgraph,
        /*max_cost=*/max_cost,
        /*rng_seed=*/rng_seed,
        /*fallback_order=*/fallback_order,
        /*old_linearization=*/m_linearization,
        /*is_topological=*/IsTopological());
    // Postlinearize to improve the linearization (if optimal, only the sub-chunk order).
    // This also guarantees that all chunks are connected (even when non-optimal).
    PostLinearize(m_depgraph, linearization);
    // Update the linearization.
    m_linearization = std::move(linearization);
    // Update the Cluster's quality.
    bool improved = false;
    if (optimal) {
        graph.SetClusterQuality(level, m_quality, m_setindex, QualityLevel::OPTIMAL);
        improved = true;
    } else if (max_cost >= graph.m_acceptable_cost && !IsAcceptable()) {
        graph.SetClusterQuality(level, m_quality, m_setindex, QualityLevel::ACCEPTABLE);
        improved = true;
    } else if (!IsTopological()) {
        graph.SetClusterQuality(level, m_quality, m_setindex, QualityLevel::NEEDS_RELINEARIZE);
        improved = true;
    }
    // Update the Entry objects.
    Updated(graph, /*level=*/level, /*rename=*/false);
    return {cost, improved};
}

std::pair<uint64_t, bool> SingletonClusterImpl::Relinearize(TxGraphImpl& graph, int level, uint64_t max_cost) noexcept
{