Possible to get WCC results as a file?

[erikmata]

Hi! I'm trying out G-Store to find weakly connected components and I'm wondering if it's possible to get the results from the WCC algorithm as a file.

As results, I mean: for each vertex ID -> component ID
Eg.
Vertex ID, Component ID
1, 1
2, 1
3, 1
4, 4
5, 4

Looking into the code, I can see that component ID:s are uint32, which makes me wonder if the algorithm can be used for graphs with more than 5 billion vertices?

[pradeep-k]

Printing vertex ID and is component ID: You can write code similar to following in wcc.cpp around line number 338.

for (vertex_t j = 0; j < vert_count; ++j) {
   cout << j << ":" << vert_cid[j] << endl;
}

Yes, the current algorithm can be used for over 5 billion vertices, but upper limit is unknown. Our initialization code is slightly different, so we don't initialize vertex with its its ID as component ID. Nonetheless, using 64 bits will not have any such issues.

Let me know, if you need any other information.

[erikmata]

Thank you for your quick reply! Looking into the code, I see that vert_cid is defined as a uint32 array (cid_t), so from your reply I gather that I could just replace all cid_t references with vertex_t instead? In order to be able to have more than 5 billion components. My graph has many small connected components, in the order of more than 5 billion of them. Not a regular social media graph where one single WCC normally spans the whole graph.

[pradeep-k]

I think it should work if you change cid_t to vertex_t at line 39 of wcc.h.

[erikmata]

Yes, I did a search-replace and it seems to work fine.

Thanks for the help!