Hi Justin, Thanks for the tip / source code! I thought the library would have a built-in copy constructor for converting between different types, but I guess not. On another note, since this method gives an isomorphic graph, all the properties must be copied over manually, correct? I think I'm only using vertex_name_t which is an internal property, but.. hmm.. Thanks again! Ethan On Wed, Jul 22, 2009 at 2:04 PM, Justin Leonard <justinleona@gmail.com>wrote:

Ethan Kim <ethkim <at> gmail.com> writes:

...

Hi all,The long standing question I've had for BGL is how to easily

convert a graph (using adjacency_list) from listS as vertex list to vecS. (And vice versa) I understand why there needs to be 2 different implementations depending on different uses of algorithms. But is there an easy way to convert them back and forth?Any tip would be much appreciated.Thanks,

...

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Do you mean given Graph A using listS you want to produce Graph B using vecS? How about something like this:

template<class GraphFrom,class GraphTo> void foo(const GraphFrom& from,GraphTo& to) { typedef typename GraphFrom::vertex_iterator viter; typedef typename GraphFrom::vertex_descriptor vdesc; typedef typename GraphFrom::edge_iterator eiter; typedef std::map<viter,typename GraphTo::vertex_iterator> map_t;

map_t table;

viter vi,vend; //copy vertices for(tie(vi,vend)=from.vertices(); vi!=vend; ++vi) table[*vi] = add_vertex(to);

eiter ei,eend; //copy edges for(tie(ei,eend)=from.edges(); ei!=eend; ++ei) { vdesc s = source(*ei,from); vdesc t = target(*ei,from);

add_edge(table[s],table[t]); } }

Assuming my template mangling is correct, this should produce an isomorphic graph of the corresponding type in about O( VlgV + ElgE ) time.

Justin

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I am not an asio expert by any means, though I've dabbled. YMMV. On Wed, Jul 22, 2009 at 8:25 PM, Alex Black<alex@alexblack.ca> wrote:

Does this code look ok?  Specifically, does this look like a good way to have a fixed # of threads service requests, and have each thread asychronously write out the response to their client?

Seems like the right thing to do.

In the code below, I left out HandleHttpRequest, and that function parses the request, does some work, and writes out the response 8kb at a type, using async_write.

note: the threads don't wait until the previous async_write is done, they each just keep calling async_write until all their data is out. (but they are careful to make sure their buffers are around for long enough)

Based on what I've read here recently I understand that each async_write is done in succession. This may make a difference on systems with more cores, even if you aren't seeing any problems. So you probably need a handler for the async_write that does successive async_writes until everything is written.

 [...] void CBaseWebServer::StartAsync(int port) { [...]  for ( int i = 0; i < numberOfThreads; i++ )  {   // Fire up a thread to run the IO service   shared_ptr<thread> pThread = shared_ptr<thread>(new thread(bind(&CBaseWebServer::RunIoService, this, i)));

N threads entering this->RunIoService...

 [...] void CBaseWebServer::RunIoService(int threadId) {  m_pPerThreadId.reset( new int(threadId) );

N threads resetting what appears to be a single shared pointer; I'm assuming its a shared_ptr. The problem is that a shared_ptr *instance* isn't thread-safe, so having N threads independently resetting and assigning it is going to cause problems (the reference counting *is* thread-safe, but each thread needs its own shared_ptr, each pointing to the same thing). Having said that, I don't see the purpose of the pointer anyway, as it isn't used in the code sample. Not sure about the error handling on accept errors; I might have it call StartAccept from HandleAccept regardless of the error, though there might be some errors I'd give up on.