Multi-dimensional metadata support?

[xiangyh9988]

Thanks for your excellent work!

Recently, after reading paper A Map Equation with Metadata: Varying the Role of Attributes in Community Detection, I try to use the set_meta_data python interface to add metadata to some nodes in the graph and it works greatly. Then I try to set multi-dim vector as the metadata for each node, as another paper Partitioning Networks with Node Attributes by Compressing Information Flow did.

I firstly modify the input args of Network::addMetaData function in Network.cpp to receive metadata with the data type of vector<float> (the original type is vector<int>). However, when I step further to read the C++ codes, I found that only the first element of vector is added into the metaCollection, e.g. metaCollection.add(node.metaData[0], weightByFlow ? node.data.flow : m_unweightedNodeFlow); in MetaMapEquation.cpp.

So, infomap cannot support the multi-dim metadata for now? I'm not sure, so open this issue asking for help. Thanks in advance!

[xiangyh9988]

I try to modify the codes to support the multi-dim metadata, while I'm not sure whether it is right. And, the clustering performance in my project is not improved, which might mean I misunderstand the use of multi-dim metadata.

The steps are as follows:

1. The input arguments of metaCollection.add in MetaMapEquation.cpp. (There are several calls of metaCollection.add and I just post one example here.)

   // The original code
   metaCollection.add(node.metaData[0], weightByFlow ? node.data.flow : m_unweightedNodeFlow);
   // The modified code
   metaCollection.add(node.metaData, weightByFlow ? node.data.flow : m_unweightedNodeFlow);

2. Functions in MetaCollection.h. Mainly convert the original unsigned int meta to std::vector<float> metaData. In my trial, the key of m_metaToFlowCount is the dimensional of metadata rather than the value of meta (i.e. the original setting). For example, if we use the 3-dim vector as the metadata, the m_metaToFlowCount looks {0: 0.7, 1: 0.1, 2: 0.2}. The modified codes are:

    // metaData[i] * flow: follow the weighted sum of CME in paper Partitioning Networks with Node Attributes by Compressing Information Flow
   void add(std::vector<float> metaData, double flow = 1.0)
   {
       m_total += flow;
       for (unsigned int i = 0; i < metaData.size(); ++i) 
       {
           m_metaToFlowCount[i] += metaData[i] * flow;
       }
    }
   void add(std::vector<float> metaData, const FlowCount& flow)
   {
     m_total += flow;
     for (unsigned int i = 0; i < metaData.size(); ++i)
     {
         m_metaToFlowCount[i] += metaData[i] * flow.flow;
     }
   }
   void add(unsigned int metaDim, const FlowCount& flow)
   {
       m_metaToFlowCount[metaDim] += flow;
   }
   void add(const MetaCollection& other)
   {
     m_total += other.m_total;
     for (auto& it : other) {
       auto metaDim = it.first;
       auto& flowCount = it.second;
       add(metaDim, flowCount);
     }
   }
   // the remove function are modified similarly and are omitted to save space here
   // the function to calculate entropy is also similar to the original one
   double calculateEntropy()
   {
       double metaCodelength = 0.0;
       for (auto& it : m_metaToFlowCount)
       {
           if (it.second.flow > 0) {
               metaCodelength -= infomath::plogp(it.second.flow/m_total.flow);
        }
    }
    return m_total.flow * metaCodelength;
   }

   Honestly, it seems that there is no obvious difference between the calculation of original 1-dim metadata and CME, which confuses me.

3. Feed the multi-dim metadata with the type of vector<float> to set_meta_data and run infomap.

The above is just a simple trial and I'm still a little confused about how to use multi-dim metadata. Hope for your help and thanks in advance!

[danieledler]

Hi @xiangyh9988 and thanks for your testing! You are right that the support for multi-dimensional metadata was only slightly prepared but not yet implemented. Unfortunately I can't check it now but will check it in a couple of weeks if the issue is still open.

[xiangyh9988]

Hi @xiangyh9988 and thanks for your testing! You are right that the support for multi-dimensional metadata was only slightly prepared but not yet implemented. Unfortunately I can't check it now but will check it in a couple of weeks if the issue is still open.

Ok, I see. It doesn't matter and it's just a simple attempt.

For now, the multi-dim metadata is not important for me, because the design of metadata vector in my project is not reasonable. That's to say, in a short time, I will not try to use multi-dim metadata.

So I will close this issue and hope you will release a official version supporting multi-dim metadata.

[xiangyh9988]

Thanks for your reply! Hope for the new version!