gserialized_spgist_picksplit_2d()

PGDLLEXPORT Datum gserialized_spgist_picksplit_2d

(

PG_FUNCTION_ARGS

)

Definition at line 337 of file gserialized_spgist_2d.c.

{
        spgPickSplitIn *in = (spgPickSplitIn *)PG_GETARG_POINTER(0);
        spgPickSplitOut *out = (spgPickSplitOut *)PG_GETARG_POINTER(1);
        BOX2DF *centroid;
        int median, i;
        double *lowXs = palloc(sizeof(double) * in->nTuples);
        double *highXs = palloc(sizeof(double) * in->nTuples);
        double *lowYs = palloc(sizeof(double) * in->nTuples);
        double *highYs = palloc(sizeof(double) * in->nTuples);
 
        /* Calculate median of all 4D coordinates */
        for (i = 0; i < in->nTuples; i++)
        {
                BOX2DF *box = (BOX2DF *)DatumGetPointer(in->datums[i]);
 
                lowXs[i] = (double)box->xmin;
                highXs[i] = (double)box->xmax;
                lowYs[i] = (double)box->ymin;
                highYs[i] = (double)box->ymax;
        }
 
        qsort(lowXs, in->nTuples, sizeof(double), compareDoubles);
        qsort(highXs, in->nTuples, sizeof(double), compareDoubles);
        qsort(lowYs, in->nTuples, sizeof(double), compareDoubles);
        qsort(highYs, in->nTuples, sizeof(double), compareDoubles);
 
        median = in->nTuples / 2;
 
        centroid = palloc(sizeof(BOX2DF));
 
        centroid->xmin = (float)lowXs[median];
        centroid->xmax = (float)highXs[median];
        centroid->ymin = (float)lowYs[median];
        centroid->ymax = (float)highYs[median];
 
        /* Fill the output */
        out->hasPrefix = true;
        out->prefixDatum = PointerGetDatum(centroid);
 
        out->nNodes = 16;
        out->nodeLabels = NULL; /* We don't need node labels. */
 
        out->mapTuplesToNodes = palloc(sizeof(int) * in->nTuples);
        out->leafTupleDatums = palloc(sizeof(Datum) * in->nTuples);
 
        /*
         * Assign ranges to corresponding nodes according to quadrants relative to the "centroid" range
         */
        for (i = 0; i < in->nTuples; i++)
        {
                BOX2DF *box = (BOX2DF *)DatumGetPointer(in->datums[i]);
                uint8 quadrant = getQuadrant4D(centroid, box);
 
                out->leafTupleDatums[i] = PointerGetDatum(box);
                out->mapTuplesToNodes[i] = quadrant;
        }
 
        pfree(lowXs);
        pfree(highXs);
        pfree(lowYs);
        pfree(highYs);
 
        PG_RETURN_VOID();
}

References centroid(), compareDoubles(), and getQuadrant4D().

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