CCARTree serialization/deserialization error

[tt83]

I'm trying to serialize/deserialize a CCARTree object in C++, but when I call load_serializable I'm getting an error: In file ~/Library/shogun-develop/src/shogun/base/Parameter.cpp line 2212: TParameter::new_sgserial(): Class CBinaryTreeMachineNode' was not listed during compiling Shogun :( ... Can not construct it form_root'! Fragment of code:

        {
            auto tree = new shogun::CCARTree(ft, shogun::PT_REGRESSION);
            tree->set_labels(std::get<1>(dataset));
            tree->set_weights(std::get<2>(dataset));
            tree->train(std::get<0>(dataset));

            auto file = new shogun::CSerializableAsciiFile("test.dat", 'w');
            if (!tree->save_serializable(file))
            {
                std::cerr << "Error saving file" << std::endl;
            }
            file->close();
            SG_UNREF(file);
            SG_UNREF(tree);
        }

        auto tree = new shogun::CCARTree();
        auto file = new shogun::CSerializableAsciiFile("test.dat", 'r');
        if (!tree->load_serializable(file))
        {
            std::cerr << "Error loading file" << std::endl;
            file->close();
            SG_UNREF(file);
            SG_UNREF(tree);
            return -1;
        }
        file->close();
        SG_UNREF(file);

[karlnapf]

Thanks for reporting this I will investigate and get back to you

[karlnapf]

3537

[zrlkau]

Hi @karlnapf,

I ran into the same issue with 6.0.0 (shogun-6.0.0-4.fc26) and with the latest git code (d8c84e90df99757aef7ebd43ade332dad5bbc8e7) while I was trying to load a CARTree in C++ that I trained and serialized in Python. Do you have an outlook on when this might be fixed (or a workaround for now, since I'm working towards a looming paper submission deadline).

thanks, Michael

[karlnapf]

Ah yes this one. I’ll try to have a look later today. Pls ping again next week if nothing happened. This is definitely something that needs fixing asap

[zrlkau]

Thanks for looking into it @karlnapf. I dug into it a little bit myself and I found that one problem might be that in src/shogun/multiclass/tree/BinaryTreeMachineNode.h the class definition is split across multiple lines, i.e.

template <typename T>
class CBinaryTreeMachineNode
       : public CTreeMachineNode<T>

instead of

template <typename T> class CBinaryTreeMachineNode : public CTreeMachineNode<T>

If I change that, then src/shogun/base/class_list.cpp.py picks it up (but unfortunately, twice, as simple and as template class - I manually removed it as simple class.) and adds the necessary functions for it into class_list.cpp. Unfortunately, I still get the same error (which is somewhat confusing to me, because I found _ZL28__new_CBinaryTreeMachineNodeN6shogun14EPrimitiveTypeE in libshogun.so):

[...]/shogun/src/shogun/base/Parameter.cpp line 2210: TParameter::new_sgserial(): Class CBinaryTreeMachineNode was not listed during compiling Shogun :( ... Can not construct it for m_root![GCDEBUG] unref() refcount 4294967295, obj SerializableAsciiFile (0x7f24b4008f50) destroying

Update: It's because the object it tries to deserialize is a CBinaryTreeMachineNode which it can't because the corresponding 'case' statement is empty.

[karlnapf]

Just briefly looked into this. Unfortunately there is some deeper issues causing this. I give it a shot fixing later.

If it takes too much time: this issue will be resolved once we have the new Parameter/serialisation framework in place which is high priority it also a lot of work.

On Thu, 12 Apr 2018 at 12:22, zrlkau notifications@github.com wrote:

Thanks for looking into it @karlnapf https://github.com/karlnapf. I dug into it a little bit myself and I found that one problem might be that in src/shogun/multiclass/tree/BinaryTreeMachineNode.h the class definition is split across multiple lines, i.e.

template class CBinaryTreeMachineNode : public CTreeMachineNode

instead of

template class CBinaryTreeMachineNode : public CTreeMachineNode

If I change that, then src/shogun/base/class_list.cpp.py picks it up (but unfortunately, twice, as simple and as template class - I manually removed it as simple class.) and adds the necessary functions for it into class_list.cpp. Unfortunately, I still get the same error (which is somewhat confusing to me, because I found _ZL28__new_CBinaryTreeMachineNodeN6shogun14EPrimitiveTypeE in libshogun.so):

[...]/shogun/src/shogun/base/Parameter.cpp line 2210: TParameter::new_sgserial(): Class CBinaryTreeMachineNode was not listed during compiling Shogun :( ... Can not construct it for m_root![GCDEBUG] unref() refcount 4294967295, obj SerializableAsciiFile (0x7f24b4008f50) destroying

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[zrlkau]

Hi @karlnapf ,

thanks for looking into it. I was afraid that it's something more fundamental since that case isn't covered in any templated class. If you can find a fix, it'd really appreciate it but I understand that it's not a simple problem.

thanks, Michael

[karlnapf]

The reason is not that this case is not covered in templated classes (or at least that is easy to fix), but the problem is that the tree implementations were never written in a way that they can be serialized (which is our bad for having not enforced that back when the GSoC student wrote this).

I opened an issue that suggests a workaround #4242

[karlnapf]

We might pick this up at this weekend's hackathon, or maybe delegate it to a GSoC student, as it is a cool task to learn more about shogun's internals.