GraphGrow in SVN now has code to calculate the **Hausdorff
dimension** of the generated fractal. However, this calculation
is only guaranteed to be valid if an **open set condition**
holds. Moreover, there is **no algorithm** to check if
the condition holds (because there is no algorithm to construct the
feasible open sets required).

I guess I'll have to add a big fat warning sticker on the info pane of GraphGrow saying that the calculated dimension isn't necessarily valid, but it's frustrating that it seems impossible to check algorithmically if it's valid or not.

References

- A Fractal Dimension Estimate For A Graph-Directed IFS Of Non-Similarities -- G A Edgar, Jeffrey Golds
- Multifractal Decompositions Of Digraph Recursive Fractals -- G A Edgar, R Daniel Mauldin
- On The Open Set Condition For Self-Similar Fractals -- Christoph Bandt, Nguyen Viet Hung, Hui Rao

Footnote: I'm not a professional mathematician, so my ramblings above might be completely wrong..