Hi Bruce and list, I think I almost have a decent IFEFFIT script for my averaging problem. However, while looking at the IFEFFIT command that Athena uses to merge files I thought of a few questions. When merging the energy scales of the various files, why did you choose to use a quadratic interpolation rather than a linear or spline interpolation? Also, I notice that Athena sends a lot of commands that look like set vpkr.energy = vpkr.energy+0 or set yybe.merge = qinterp(yybe.energy+0, yybe.xmu, vpkr.energy) to IFEFFIT when merging files. What does the +0 do at the end of the array? I've been looking through the IFEFFIT documentation, but can't seem to find anything that clarifies that command. Also, if I try and issue the command at the IFEFFIT command line I get an error that reads "** cannot set scalar value to array **". So why can Athena issue the command and I can't? Thanks! Matt -- ******************************************* Matthew Ginder-Vogel Post Doctoral Researcher Center for Critical Zone Research Environmental Soil Chemistry University of Delaware http://ag.udel.edu/SoilChem/gindervogel.html (302) 831-0608 mattgv@udel.edu *******************************************