Hi Bruce and Matt, I've just spent a few hours trying to track down a bug that showed up in one of my complicated Artemis files. I've boiled it down to the point where I can make it happen in one of the example files, although of course in this context it looks a little pointless. At any rate, take Ifeffit/examples/Artemis/Cu/oneshell.apj, and change the sigma2 for path 1 to: (1)*sigsqr + signor*(1) and run a fit. For me, that generates the ifeffit message: path(1, sigma2 = (1)*sigsqr + signor*(1)) syntax error: (1)*sigsqr)+signor*((1) parentheses not used properly and causes a sigma2 of 0 to be used. Artemis doesn't report any error; you have to look in the ifeffit buffer or notice that you're getting a funny value of sigma2 (i.e. 0) assigned to path 1. Now change the sigma2 to read: (1)*sigsqr + signor*(1)*1 and everything works fine. Weird, huh? I'm using Artemis 0.7.015 and ifeffit 1.2.7 on Windows XP. --Scott Calvin Sarah Lawrence College