fibonacci series

[srijan sharma]

hi all,
i could not understand the simple example given in java concurent programming book at page 349 under fork/join sec 4.4.1. there is a code to calculate fibonacci series
in a parallel fashion using threads.class taskrunnergroup is also not defined. can anybody explain it ...also what fork/join will do??
regards
srijan

[Rahul Mahindrakar]

Could you please post the code example.

[srijan sharma]

hi ,
the code is

class fib extends fjtask{
static final int sequentialthreshold=13;
volatile int number;
fib(int n)
{
number=n;
}
int getanswer()
{
if(!isdone())
throw new IllegalStateException("not yet computed");
return nmber;
}
public void run()
{
int n=number;
if(n<=sequentialthreshold)
number=seqfib(n);
else{
fib f1= new fib(n-1);
fib f2= new fib(n-2);
coinvoke(f1,f2);
number=f1.number+f2.number;
}
}
public static void main(String args[])
{
try
{
int groupsixe=2;
int num=35;
fjtaskrunnergroup group = new fjtaskrunnergroup(groupsize);
fib f = new fib(num);
group.invoke(f);
int result=f.getanswer();
Syetm.out.println("answer"+result);
}
catch(InteruptedException ex){}
}
}
 
/* coinvoke(fjtask t,fjtask u)
{
t.fork();
invoke(u);
t.join();
}
*/

regards
srijan

[This message has been edited by Rahul Mahindrakar (edited January 31, 2001).]