What are the best tools / frameworks / libraries available to implement and run algorithms on graphs?
In particular I need a tool that can load a set of nodes, edges and values assigned to these edges and then allows me to perform operations on them.
I already found R but I'm wondering if there is a more "programmer friendly" tool available?
Are you talking about really large graphs -- 10+ GB? Google uses it's own framework Pregel for that: http://googleresearch.blogspot.com/2009/06/large-scale-graph-computing-at-google.html
There now are quite a few open-source frameworks that copy that approach, some are discussed in http://blog.acaro.org/entry/google-pregel-the-rise-of-the-clones.
For smaller graphs that fit within the memory of a single computer there have been libraries for a long time, probably the most well known one is Boost Graph.
Depending on what kind of operations you're talking about, I used yFiles a few years ago and found it to be extremely powerful for graph visualisation - as well as having best-of-breed algorithms for things like automatic layout, shortest path analysis etc
The main library is Java but there are also .NET and Flex ports.
Could be worth looking at :)
