+sn_network_t *sn_network_combine (sn_network_t *n0, sn_network_t *n1,
+ int is_power_of_two);
+sn_network_t *sn_network_combine_bitonic (sn_network_t *n0, sn_network_t *n1);
+sn_network_t *sn_network_combine_odd_even_merge (sn_network_t *n0, sn_network_t *n1);