Re: [Boost-users] [Boost.MPI] question about serializingcustomobject

Subject: Re: [Boost-users] [Boost.MPI] question about serializingcustomobject
From: Robert Ramey (ramey_at_[hidden])
Date: 2010-08-26 18:14:51

Cristobal Navarro wrote:
> i made some progress while we were mailing between us.
> 
> 
> first of all, im trying to see if my object can be serialized /
> deserialized in the common way without going into MPI yet. 

good idea - one thing at a time.

> objects are Lattices, they have Nodes and Edges. nothing more.

> it compiles and links ok, and when i test serialization /
> deserialization with the following code..: 
>  
>                 printf("serializing to binlat.x...\n");
>                 //!file mode
>                 /*
>                 std::ofstream ofs("binlat.x", ios::binary);
>                 boost::archive::binary_oarchive oa(ofs);
>                 */
>                 oa << *(this->lat);
>                 ofs.close();
>                 lat->print(); //check what lattice im serializing
>                 //!Deserialization - read file  binlat.x and
> reconstruct 
>                 printf("reconstructing serialized binlat.x...\n");
>                 Lattice nl;
>                 std::ifstream ifs("binlat.x", ios::binary);
>                 boost::archive::binary_iarchive ia(ifs);
>                 //!deserialize object
>                 ia >> nl;
>                 ifs.close();
>                 nl.print();
> 

Hmmm- what surrounds this?

>                 oa << *(this->lat);

doesn't look right to me.  coincidentally, this same construct is used on another thread

anyay

try

{
   const class Lattice lat ...
    ...
    ar << lat
}

that might work better.

Robert Ramey

> 
> 
> i get bad errors when deserializing, complaining about a bool and
> char. 
> serializing to binlat.x...
> Lattice::print().....START
> Nodes=2   Edges= 1
> Node[0] sp=1 ext=1
> Linked to edge 2 (Node 3 or 0 )
> Node[3] sp=1 ext=2
> Linked to edge 2 (Node 3 or 0 )
> Lattice::print().....END
> [enter]
> reconstructing swerialized binlat.x...
> [enter]
> plattice:
> /usr/local/include/boost/archive/basic_binary_iprimitive.hpp:98: void
> boost::archive::basic_binary_iprimitive<Archive, Elem,
> Tr>::load(bool&) [with Archive = boost::archive::binary_iarchive,
> Elem = char, Tr = std::char_traits<char>]: Assertion `0 == i || 1 ==
> i' failed.     
> [lenovo00:29384] *** Process received signal ***
> [lenovo00:29384] Signal: Aborted (6)
> [lenovo00:29384] Signal code:  (-6)
> [lenovo00:29384] [ 0] [0xfea410]
> [lenovo00:29384] [ 1] /lib/tls/i686/cmov/libc.so.6(abort+0x182)
> [0xd41a82] 
> [lenovo00:29384] [ 2]
> /lib/tls/i686/cmov/libc.so.6(__assert_fail+0xf8) [0xd37718] 
> [lenovo00:29384] [ 3]
> ..
> ..
> *** End of error message ***
> 
> 
> i started debugging, and realized that the problem is completely gone
> when i remove "edges" from the serialization members of "Lattice"
> object.  
> its weird, because "edge" is a map of <int, Edge> and much simplier
> than "nodes" which does work. obviously i cannot continue without
> edges, so i need to fix it somehow, but i dont understand the error
> related to edges, maybe is something im not seeing.   
> 
> 
> dont get distracted by the messy code, i had to edit it a little to
> focus on the case. 
> regards
> Cristobal
> 
> 
> 
> 
> 
> 
> On Thu, Aug 26, 2010 at 4:35 PM, Robert Ramey <ramey_at_[hidden]> wrote:
> 
>> Change the "would" into "is": it is possible to mix Boost.MPI with
>> Boost.Serialization. Any objext that can be serialized can be sent by
>> Boost.MPI. This was actually the basic idea behind Boost.MPI, to use
>> Boost.Serialization to pack and unpack MPI buffers, or to create
>> custom MPI datatypes.
> 
> On thing that I never understood is why you need MPI data types at
> all. 
> If one is serializing (packing) to a binary array, and sending that,
> what 
> hae MPI data types have to do with it.
> 
> If one were using heterogenious machines, I could understand the
> usage of MPI types. But as I understand it, the MPI serialization
> presumes 
> that the machines are binary compatible.  So I'm just not seeing this.
> 
> Robert Ramey
> 
> 
> 
> _______________________________________________
> Boost-users mailing list
> Boost-users_at_[hidden]
> http://lists.boost.org/mailman/listinfo.cgi/boost-users
> 
> 
> 
> 
> 
> 
> _______________________________________________
> Boost-users mailing list
> Boost-users_at_[hidden]
> http://lists.boost.org/mailman/listinfo.cgi/boost-users