func start_worker(worker_id int) {
logger := log.New(os.Stdout, fmt.Sprintf("WORKER(%d): ", worker_id), log.Ldate|log.Ltime)
gl_min_cost := tsp_types.GlobalCostType{}
gl_min_cost.Init(tsp_types.POSITIVE_INF)
curr_task_id := -1
runtime.GOMAXPROCS(runtime.NumCPU())
destination := "127.0.0.1:5000"
logger.Println("worker: connect to ", destination)
conn, err := net.Dial("tcp", destination)
if err != nil {
logger.Printf("dial error: %v", err)
}
curr_task_info := CurrTaskInfo{curr_task_id, gl_min_cost}
go listen_server(&conn, logger, &curr_task_info)
}
