Property map from graph xml

graph-tool
1

Hi, I have quickly explored the documentation. So I am sorry if I have
overlooked something essential.

I use a graph file exported from gephi (xml file(graphml))

</node>
<node id="672712520">
<data key="label">672712520</data>
<data key="size">10.0</data>
<data key="r">153</data>
<data key="g">153</data>
<data key="b">153</data>
<data key="x">25781.25</data>
<data key="y">14798.744</data>
</node>

However, the the node id object is not listed as a property map (in my case
it's not the same as the label for all nodes) Is it possible to access this
value?

Second, what is the optimal method to find the vertice number for a known
property value(ID or label)?

Thanks,
Håvard

2

Hi,

Hi, I have quickly explored the documentation. So I am sorry if I have
overlooked something essential.

I use a graph file exported from gephi (xml file(graphml))

</node>
<node id="672712520">
<data key="label">672712520</data>
<data key="size">10.0</data>
<data key="r">153</data>
<data key="g">153</data>
<data key="b">153</data>
<data key="x">25781.25</data>
<data key="y">14798.744</data>
</node>

However, the the node id object is not listed as a property map (in my
case it's not the same as the label for all nodes) Is it possible to
access this value?

The id of a vertex is not interpreted to be a property. This is simply
used internally in the graphml format to differentiate between
vertices. In case the file uses "canonical" indexes (indexes go from n0
to nN-1), then the ids correspond to the vertex index used in
graph-tool, otherwise the ids are not visible after the graph is loaded.

If you want the ids to be visible, you have to mirror them as a
an actual property.

Second, what is the optimal method to find the vertice number for a
known property value(ID or label)?

There is a find_vertex() function available, which does what you want,
but it is O(N) (in C++). If you want to do it faster, you have to
build your own dictionary...

Cheers,
Tiago

3

OK, I tried this

g = load_graph("/home/havard/Untitled.xml",file_format='xml')

name = g.vertex_properties["label"]

print find_vertex(g,name,'1313754909')

- why does find_vertex return multiple matches? I in my case the nodes have
a unique label.

4

Hm, this is because you just found a bug in the string ordering
code... I've just corrected it in the git version.

Cheers,
Tiago

5

Hi, tried the git version.

The compiler gave no error but when imported in python

RuntimeError: module compiled against API version 6 but this version of
numpy is 4
Traceback (most recent call last):

6

You have to double check if you compiled graph-tool against the same
version of numpy which is being loaded...

Cheers,
Tiago

7

Thanks, I had two versions of numpy installed.

Another question:
With the Search algorithms how do I select I target node?

8

I'm not sure I understand what you mean. Are you talking about
find_vertex() or the functions in the search module?

Cheers,
Tiago

9

Sorry, I meant the functions in the search module.

Also, with your latest version find_vertex() now works correctly on int but
not for character ID's.
If the ID is a character multiple nodes there are multiple matches

10

Sorry, I meant the functions in the search module.

For the search functions you have to subclass the appropriate visitor
classes in order to do something useful. You do not usually just want to
find a vertex, you want to record something about the search...

Also, with your latest version find_vertex() now works correctly on int but
not for character ID's.
If the ID is a character multiple nodes there are multiple matches

I cannot reproduce this. Would you be able to provide an example?

Cheers,
Tiago