thread_local_state.h

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#ifndef SOCNETV_THREAD_LOCAL_STATE_H
#define SOCNETV_THREAD_LOCAL_STATE_H
 
#include "engine/per_source_scratch.h"
 
#include <QVector>
#include <QtGlobal>
 
struct ThreadLocalState
{
    // Reused SSSP scratch — reset once per source via pss.resetPerSource().
    PerSourceScratch pss;
 
    // Partial betweenness centrality sums, indexed by vertex position.
    // Each source contributes pss.delta[wi] for every intermediate vertex w != s
    // instead of calling vertex->setBC() directly (which would race across threads).
    // Post-loop: vertex[wi]->setBC( sum over all threads of partialBC[wi] )
    QVector<qreal> partialBC;
 
    // Partial stress centrality sums, indexed by vertex position.
    // Each vertex ui that is a direct predecessor of some w on the final settled shortest-path
    // DAG from a source increments partialSC[ui] by 1 - accumulated in the same Brandes
    // back-propagation loop that computes partialBC, from pss.Ps/pss.sigma, not during relaxation.
    // Post-loop: vertex[ui]->setSC( sum over all threads of partialSC[ui] )
    QVector<qreal> partialSC;
 
    // Sum, across all sources this thread has processed, of each source's final-distance sum
    // (accumulated in the APSP write-back loop from tls.pss.dist[], after SSSP has fully
    // settled - correct for both BFS and Dijkstra).
    // Reduced into graph.addToDistanceSum() after the parallel loop.
    qreal totalDistanceSum = 0;
 
    // Maximum geodesic distance (diameter) seen by this thread. qreal, not int: on a weighted
    // graph this is routinely fractional, same as totalDistanceSum.
    // Post-loop: graph.setDiameterCached( max over all threads of maxDiameter )
    qreal maxDiameter = 0;
 
    // Accumulated Power Centrality and Standardised Power Centrality sums.
    // Replaces direct graph.sumPC += and graph.sumSPC += inside the source loop
    // (those graph members are public but would race across threads).
    // Reduced into graph.sumPC and graph.sumSPC after the parallel loop.
    qreal totalSumPC  = 0;
    qreal totalSumSPC = 0;
 
    // Initialise all per-vertex arrays to totalV slots.
    // Must be called once per thread before the parallel source loop starts.
    void allocate(int totalV)
    {
        pss.allocate(totalV);
        partialBC.fill(0.0, totalV);
        partialSC.fill(0.0, totalV);
    }
};
 
#endif // SOCNETV_THREAD_LOCAL_STATE_H