I'm using Mathematica 7.0 to evaluate a very large expression, involving spence functions and limits. The notebook evaluates fine, all the way down to the LogPlot command which then takes forever to evaluate. I've left it running overnight and it still hasn't produced the plot. Is this normal? This step was running very quickly, but then I edited the code in a minor way and now it takes ages. Any ideas on whether it might be crashing? no error messages are output, and it declares itself to still be running. Many thanks for any ideas.