Re: [Boost-users] Graph-Based Threaded Algorithms

Subject: Re: [Boost-users] Graph-Based Threaded Algorithms
From: James C. Sutherland (James.Sutherland_at_[hidden])
Date: 2008-12-23 13:09:44

>
> For the sake of argument, let's say your nor using a thread pool and  
> don't have any limits on the number of threads you can spawn. You  
> could associate a condition variable with each vertex using a  
> property map, and make that available to your BFS visitor. By  
> overriding on_tree_edge, you can get access to the parent/child  
> vertices in the BFS tree. Your child vertex can spawn a new thread  
> and wait on the condition variable associated with the parent. IIRC  
> this means that you can have multiple children waiting on the  
> parent. When the parent thread is done, it notifies the condition  
> variable, waking up all of its dependant children. Of course,  
> children wouldn't have to wait if the parent had already finished,  
> so you'll probably want to make sure that there's a valid and  
> initialized condition variable before waiting on it.
>

Thank you for the tips, Andrew.  What about the case where we have a  
child waiting on multiple parents?  That seems like a bit more  
difficult case...?

James