Re: [igraph] snap & igraph

[Tamás Nepusz]

I am not aware of any OOTB converters between SNAP and igraph graph objects, 
and building one that works reliably would probably require careful 
consideration as the graph models of SNAP and igraph are slightly different. 
For instance:

- igraph requires node IDs to be contiguous integers starting at zero while 
SNAP doesn’t, so SNAP objects can only be mapped to igraph graphs by using a 
separate “id” vertex attribute on the igraph side that corresponds to the 
original (non-contiguous) SNAP ID

- snap.TUNGraph and snap.TNGraph do not support multiple edges between nodes 
(as far as I know), so mapping igraph graphs with multiple edges back to a 
snap.TUNGraph or snap.TNGraph is not possible (only to a snap.TNEANet). 
Attributes are also supported only with tNEANet.

- Attributes in a snap.TNEANet are “typed” so you cannot mix attributes of 
different type for the same attribute name. igraph graphs exploiting this 
feature (such as having an integer attribute with occasional None values to 
represent missing data) have to be handled during the conversion explicitly.

- snap.TNEANet supports integers, floats and strings only, so any other 
attribute type in igraph (e.g., Unicode, or an arbitrary Python object) has to 
be handled explicitly.

On the other hand, if your graphs do not have attributes and/or you only want 
to preserve the structure, you can get an edge list from igraph using the 
get_edgelist() method and then use that to construct the same graph in SNAP.

--  
T.

------------------------------------------------------
From: Jeff Hemsley address@hidden
Reply: Help for igraph users address@hidden
Date: 10 April 2014 at 16:04:47
To:address@hidden address@hidden, Help for igraph users address@hidden
Subject:  Re: [igraph] snap & igraph

> Hi Sam,
> Did anyone answer your question? I'm curious too.
>  
> On Wed, Apr 9, 2014 at 2:30 PM, Sam Steingold wrote:
> > Hi,
> > Both igraph and SNAP (http://snap.stanford.edu/) provide Python
> > interface.
> > Is there a way to use both on the same graph?
> > I.e., are there any OOTB converters between SNAP and igraph objects?
> > Thanks!
> > --
> > Sam Steingold (http://sds.podval.org/) on darwin Ns 10.3.1265
> > http://www.childpsy.net/ http://mideasttruth.com http://jihadwatch.org
> > http://thereligionofpeace.com http://camera.org 
> > http://islamexposedonline.com  
> > A number problem "solved" with floats turns into 1.9999999999999998 
> > problems.
> >
> > _______________________________________________
> > igraph-help mailing list
> > address@hidden
> > https://lists.nongnu.org/mailman/listinfo/igraph-help
>  
>  
>  
> --
>  
> --
> Jeff Hemsley
> Doctoral Candidate
> Author of Going Viral, Polity Press
> The Information School
> University of Washington
> http://staff.washington.edu/jhemsley/
> http://somelab.net/author/jhemsley/
> address@hidden
>  
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