Hi! I am using the BGL to represent a fractal structure which I iteratevley grow. As I intend to handle large structures I usually preallocate the required space for the final fractal in the beginning. My construction process then uses the graph object to put in new edges into the same graph object. Now, if I always use the same graph object things get messed up for large fractals. However, if I use 2 graph structures, one which represents the last and one the comming generation, everything is ok (which doubles memory requirements for nothing). I have no clue what the problem here is. For small fractals both schemes produce correct fractals, but not for large ones. I suspect that there are some really strange problems here with allocated memory going on. BTW, is there a way to preallocate the required memory for the edges of a adjacency_list graph? I do know ahaed how many edges in total and how many edges per vertex will be in the final graph, so that I could preallocate memory if it is possible. Preallocating vertices is easy... In case someone may have an idea, but needs the code I am having trouble with, no problem, just contact me. Thanks in advance, Sebastian