public void init(){}
public void start(){
if(th == null){
th = new Thread(this);
th.start();
}
}

public void stop(){
if (th != null) {
th.stop();
th = null;
}
}

public void run() {
while (true) {
double t;
double T = 1.0;
double N = 100;
double dt = T/N;
double k11,k12,k13,k14,k21,k22,k23,k24,k31,k32,k33,k34,k41,k42,k43,k44;