Function cbm_leiden

src/store/store.c:7110–7208

}

int cbm_leiden(const int64_t *nodes, int node_count, const cbm_louvain_edge_t *edges,
               int edge_count, double resolution, cbm_louvain_result_t **out, int *out_count) {
    if (node_count <= 0) {
        *out = NULL;
        *out_count = 0;
        return CBM_STORE_OK;
    }
    int n = node_count;
    double gamma = resolution > 0.0 ? resolution : 1.0;

    cbm_louvain_result_t *result = malloc((size_t)n * sizeof(*result));
    if (!result) {
        return CBM_NOT_FOUND;
    }
    for (int i = 0; i < n; i++) {
        result[i].node_id = nodes[i];
        result[i].community = i;
    }

    /* Build deduplicated undirected edge weights, then a CSR graph. */
    int *wsi;
    int *wdi;
    double *ww;
    int wn;
    louvain_build_weights(nodes, n, edges, edge_count, &wsi, &wdi, &ww, &wn);
    cbm_lg_t g;
    int built = (wn > 0) ? lg_build(n, wsi, wdi, ww, wn, &g) : CBM_NOT_FOUND;
    free(wsi);
    free(wdi);
    free(ww);
    if (built != CBM_STORE_OK) {
        /* No edges (or allocation failure): every node is its own community. */
        *out = result;
        *out_count = n;
        return CBM_STORE_OK;
    }

    double twom = 0.0;
    for (int i = 0; i < n; i++) {
        twom += g.k[i];
    }

    int *orig = malloc((size_t)n * sizeof(int)); /* original node -> current graph node */
    int *comm = malloc((size_t)n * sizeof(int));
    if (twom <= 0.0 || !orig || !comm) {
        free(orig);
        free(comm);
        lg_free(&g);
        *out = result;
        *out_count = n;
        return CBM_STORE_OK;
    }
    for (int i = 0; i < n; i++) {
        orig[i] = i;
        comm[i] = i;
    }

    for (int level = 0; level < LEIDEN_MAX_LEVELS; level++) {