gserialized_gist_penalty()

Datum gserialized_gist_penalty

(

PG_FUNCTION_ARGS

)

Definition at line 1343 of file gserialized_gist_nd.c.

References gidx_edge(), gidx_union_edge(), gidx_union_volume(), gidx_volume(), gserialized_gist_union(), pack_float(), and PG_FUNCTION_INFO_V1().

Referenced by gserialized_gist_picksplit_constructsplit(), and pack_float().

{
        GISTENTRY *origentry = (GISTENTRY*) PG_GETARG_POINTER(0);
        GISTENTRY *newentry = (GISTENTRY*) PG_GETARG_POINTER(1);
        float *result = (float*) PG_GETARG_POINTER(2);
        GIDX *gbox_index_orig, *gbox_index_new;
        float size_union, size_orig, edge_union, edge_orig;

        POSTGIS_DEBUG(4, "[GIST] 'penalty' function called");

        gbox_index_orig = (GIDX*)DatumGetPointer(origentry->key);
        gbox_index_new = (GIDX*)DatumGetPointer(newentry->key);

        /* Drop out if we're dealing with null inputs. Shouldn't happen. */
        if ( (gbox_index_orig == NULL) && (gbox_index_new == NULL) )
        {
                POSTGIS_DEBUG(4, "[GIST] both inputs NULL! returning penalty of zero");
                *result = 0.0;
                PG_RETURN_FLOAT8(*result);
        }

        /* Calculate the size difference of the boxes (volume difference in this case). */
        size_union = gidx_union_volume(gbox_index_orig, gbox_index_new);
        size_orig = gidx_volume(gbox_index_orig);
        *result = size_union - size_orig;

        /* REALM 0: No extension is required, volume is zero, return edge */
        /* REALM 1: No extension is required, return nonzero area */
        /* REALM 2: Area extension is zero, return nonzero edge extension */
        /* REALM 3: Area extension is nonzero, return it */

        if( *result == 0 )
        {
                if (size_orig > 0)
                {
                        *result = pack_float(size_orig, 1); /* REALM 1 */
                }
                else
                {
                        edge_union = gidx_union_edge(gbox_index_orig, gbox_index_new);
                        edge_orig = gidx_edge(gbox_index_orig);
                        *result = edge_union - edge_orig;
                        if( *result == 0 )
                        {
                                *result = pack_float(edge_orig, 0); /* REALM 0 */
                        }
                        else
                        {
                                *result = pack_float(*result, 2); /* REALM 2 */
                        }
                }
        }
        else
        {
                *result = pack_float(*result, 3); /* REALM 3 */
        }

        POSTGIS_DEBUGF(4, "[GIST] union size (%.12f), original size (%.12f), penalty (%.12f)", size_union, size_orig, *result);

        PG_RETURN_POINTER(result);
}

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