boost::shared_ptr and stl algorithms
std::vector< boost::shared_ptr<T> > TVec; I want to write a function object to run std::for_each. to do somework against members of T and accumulate results in functor. My attempts have failed in VC7 with memory errors in my operator() method. struct fo { bool operator()( boost::shared_ptr<T>& t ) { return true; } }; Thanks in advance bille
From: "Bill Eidson" <yg-boost-users@gmane.org>
std::vector< boost::shared_ptr<T> > TVec;
I want to write a function object to run std::for_each. to do somework against members of T and accumulate results in functor. My attempts have failed in VC7 with memory errors in my operator() method.
struct fo { bool operator()( boost::shared_ptr<T>& t ) { return true; } };
Can you post a complete program that shows the problem? I see nothing wrong with the snippets above. Perhaps you try to call a member via an empty shared_ptr?
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi, can someone give an example how to "not use the built-in vertex index, and instead use a property to add my own vertex index property" (see page 223 BGL-book) for an adjacency_list? My problem is that I'm using the vecS selector for the VertexList template parameter and I need to remove vertices from my graph (but not frequently). Every time I do this, my vertex descriptors are invalidated (as described in the book). I need a solution so that I can remove some vertices and all my vertex descriptors remain valid. Thanks in advance, Michael - -- http://www.ive.uni-hannover.de # kettner@ive.uni-hannover.de -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.0.6 (GNU/Linux) Comment: For info see http://www.gnupg.org iD8DBQE9LulmkCdGnb0kVFMRAjFOAJ9EPNIOLP+vWqEJLpgzFi2pBij6MgCdFSN8 pOc9vhZRn8gAnc3JSTWJW2I= =APLS -----END PGP SIGNATURE-----
Hi Michael, You can't add your own vertex_index property to an adjacency_list with VertexList=vecS. The adjacency_list will just ignore it if you do. You can if VertexList=listS, and example/adjacency_list.cpp is an example of this. Also, you can add properties with names other than vertex_index_t to adjacency_list with VertexList=vecS. For example, you could add your own vertex_id_t property. However, this would *not* keep the vertex descriptors from being invalidated, it would just give you a vertex_id_t property that is stable. I'm not sure if the above helps... I don't know the details of what you are trying to do, but feel free to ask further questions. Cheers, Jeremy On Fri, 12 Jul 2002, Michael Kettner wrote: kettne> Hi, kettne> kettne> can someone give an example how to "not use the built-in vertex index, and kettne> instead use a property to add my own vertex index property" (see page 223 kettne> BGL-book) for an adjacency_list? kettne> My problem is that I'm using the vecS selector for the VertexList template kettne> parameter and I need to remove vertices from my graph (but not frequently). kettne> Every time I do this, my vertex descriptors are invalidated (as described in kettne> the book). I need a solution so that I can remove some vertices and all my kettne> vertex descriptors remain valid. kettne> kettne> Thanks in advance, kettne> kettne> Michael ---------------------------------------------------------------------- Jeremy Siek http://php.indiana.edu/~jsiek/ Ph.D. Student, Indiana Univ. B'ton email: jsiek@osl.iu.edu C++ Booster (http://www.boost.org) office phone: (812) 855-3608 ----------------------------------------------------------------------
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi Jeremy, thanks for your quick reply. What I do is the following: I wrote my own class representing nodes (class myNodeClass). Now I'm creating nodes in a graph, mapping each resulting vertex index to the associated myNode-object in a std::map. I hope the following code fragment is enough to give you an idea: class myNodeClass; typedef boost::adjacency_list<boost::vecS,boost::vecS, boost::bidirectionalS,boost::no_property,boost::no_property> tGraph; typedef typename boost::graph_traits < tGraph >::vertex_descriptor tNode; std::map<myNodeClass*, tNode> mapNode; tGraph myGraph; myNodeClass* myNode = new myNodeClass(); mapNode[myNode] = boost::add_vertex( myGraph ); myNodeClass* myNode2 = new myNodeClass(); mapNode[myNode2] = boost::add_vertex( myGraph ); boost::clear_vertex( mapNode[myNode], myGraph ); boost::remove_vertex( mapNode[myNode], myGraph ); mapNode.erase(myNode); And this causes trouble: the result of mapNode[myNode2] now is no longer valid. Any hint how I can avoid this? And another question: I tried to run boost::dijkstra_shortest_paths on myGraph with "listS" as VertexList template parameter, but the code fails to compile. When using "vecS" instead, everything works fine. Any idea? Best regards, Michael On Friday 12 July 2002 17:54, Jeremy Siek wrote:
Hi Michael,
You can't add your own vertex_index property to an adjacency_list with VertexList=vecS. The adjacency_list will just ignore it if you do. You can if VertexList=listS, and example/adjacency_list.cpp is an example of this.
Also, you can add properties with names other than vertex_index_t to adjacency_list with VertexList=vecS. For example, you could add your own vertex_id_t property. However, this would *not* keep the vertex descriptors from being invalidated, it would just give you a vertex_id_t property that is stable.
I'm not sure if the above helps... I don't know the details of what you are trying to do, but feel free to ask further questions.
Cheers, Jeremy
On Fri, 12 Jul 2002, Michael Kettner wrote: kettne> Hi, kettne> kettne> can someone give an example how to "not use the built-in vertex index, and kettne> instead use a property to add my own vertex index property" (see page 223 kettne> BGL-book) for an adjacency_list? kettne> My problem is that I'm using the vecS selector for the VertexList template kettne> parameter and I need to remove vertices from my graph (but not frequently). kettne> Every time I do this, my vertex descriptors are invalidated (as described in kettne> the book). I need a solution so that I can remove some vertices and all my kettne> vertex descriptors remain valid. kettne> kettne> Thanks in advance, kettne> kettne> Michael -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.0.6 (GNU/Linux) Comment: For info see http://www.gnupg.org
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Hi Michael, On Fri, 12 Jul 2002, Michael Kettner wrote: kettne> Hi Jeremy, kettne> kettne> thanks for your quick reply. kettne> What I do is the following: I wrote my own class representing nodes (class kettne> myNodeClass). Now I'm creating nodes in a graph, mapping each resulting kettne> vertex index to the associated myNode-object in a std::map. I hope the kettne> following code fragment is enough to give you an idea: kettne> That's a tough one. The easiest solution I see is switching to VertexList=listS. Do you have a reason for prefering vecS? This issue has me thinking... I see a way to change adjacency_list<VertexList=vecS> so that the vertex descriptors are stable. Now the trick is to think of a way to make this backwards compatible... Don't hold your breadth on this though... this would be a fairly large change to adjacency_list. kettne> And another question: I tried to run boost::dijkstra_shortest_paths on myGraph kettne> with "listS" as VertexList template parameter, but the code fails to compile. kettne> When using "vecS" instead, everything works fine. Any idea? Yeah, dijkstra_shortest_paths requires a vertex_index property map, which is by default obtained from the graph. You need to add vertex_index_t as a internal vertex property for your graph and initialize it with appropriate integers. Cheers, Jeremy ---------------------------------------------------------------------- Jeremy Siek http://php.indiana.edu/~jsiek/ Ph.D. Student, Indiana Univ. B'ton email: jsiek@osl.iu.edu C++ Booster (http://www.boost.org) office phone: (812) 855-3608 ----------------------------------------------------------------------
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi Jeremy, On Friday 12 July 2002 20:17, Jeremy Siek wrote:
Yeah, dijkstra_shortest_paths requires a vertex_index property map, which is by default obtained from the graph. You need to add vertex_index_t as a internal vertex property for your graph and initialize it with appropriate integers.
Must the integers I provide be in the range [0,|V|)? My code still fails to compile, the error messages i get are always like: /boost/graph/dijkstra_shortest_paths.hpp:199: passing `void *' to argument 2 of `put<void *, void *>(void **, int, void *const &)' lacks a cast or /boost/graph/relax.hpp:74: passing `void *' to argument 2 of `put<void *, void *>(void **, int, void *const &)' lacks a cast To give me (and all the others having the same problem) a hint: Could you please explain how to change the "dijkstra-example.cpp" from boost_1_28_0 to compile with "listS" as VertexIndex template? Thanks in advance, Michael - -- http://www.ive.uni-hannover.de # kettner@ive.uni-hannover.de -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.0.6 (GNU/Linux) Comment: For info see http://www.gnupg.org iD8DBQE9MWu2kCdGnb0kVFMRAt1TAJ4ywNuP8aiwtYSBtoHcM6ZpOHM17QCaA708 EJy1n2o/4c/CsWSoOvOV/p4= =a/gO -----END PGP SIGNATURE-----
Hi Michael, On Sun, 14 Jul 2002, Michael Kettner wrote: kettne> To give me (and all the others having the same problem) a hint: Could you kettne> please explain how to change the "dijkstra-example.cpp" from boost_1_28_0 to kettne> compile with "listS" as VertexIndex template? I've written up a new example, dijkstra-example-listS.cpp which uses listS as the VertexList parameter for the graph. The file is checked into boost CVS in the example directory. Cheers, Jeremy ---------------------------------------------------------------------- Jeremy Siek http://php.indiana.edu/~jsiek/ Ph.D. Student, Indiana Univ. B'ton email: jsiek@osl.iu.edu C++ Booster (http://www.boost.org) office phone: (812) 855-3608 ----------------------------------------------------------------------
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi Jeremy, thanks for providing the example. I didn't get the time to apply it to my graph as yet, but I will let you know if there should be problems doing so. Thanks so far for the great support! Michael
I've written up a new example, dijkstra-example-listS.cpp which uses listS as the VertexList parameter for the graph. The file is checked into boost CVS in the example directory.
- -- http://www.ive.uni-hannover.de # kettner@ive.uni-hannover.de -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.0.6 (GNU/Linux) Comment: For info see http://www.gnupg.org iD8DBQE9RjU6kCdGnb0kVFMRAirOAJ0cLOw7SDsuoh41gkKeiVpXrudvlgCcC+Ww bJaP7YOTvrSowP3VbnKMLyg= =FB4H -----END PGP SIGNATURE-----
Hi, Jeremy, In your email, you mentioned dijkstra has problems with listS vertices and you gave an example. I found the incremental_components.cpp has the same problem with listS vertices. Is it right? Do you have an listS example for incremental_compoents too? Or it is the problem of MSVC 6.0 again? Thanks! Vivid Jeremy Siek wrote:
Hi Michael,
On Sun, 14 Jul 2002, Michael Kettner wrote: kettne> To give me (and all the others having the same problem) a hint: Could you kettne> please explain how to change the "dijkstra-example.cpp" from boost_1_28_0 to kettne> compile with "listS" as VertexIndex template?
I've written up a new example, dijkstra-example-listS.cpp which uses listS as the VertexList parameter for the graph. The file is checked into boost CVS in the example directory.
Cheers, Jeremy
---------------------------------------------------------------------- Jeremy Siek http://php.indiana.edu/~jsiek/ Ph.D. Student, Indiana Univ. B'ton email: jsiek@osl.iu.edu C++ Booster (http://www.boost.org) office phone: (812) 855-3608 ----------------------------------------------------------------------
participants (1)
-
Bill Eidson -
Jeremy Siek -
Michael Kettner -
Peter Dimov -
Vivid Yang