fit2 opens and stores data in several files. fit.tmp is used if the function is plotted to a file. fit.dat is used as a default filename if none is specified with the wf command. The wp command stores the parameters in the file a.dat. In addition, the text output of gnuplot which is sent to stderr is written in the file gnuout. On non-unix machines, fit2 does not erase any of these files, unless it overwites them. On UNIX machines fit.tmp and gnuout are written in the /tmp . They are erased when the program exits, unless debugging is on. If the debug flag is non-zero, lamda is written to a file called lamda.sts on every successful iteration. lamda controls how much the paramerers are changed in attempting to reduce χ2, and changing how lamda is chosen would be one way to improve effeciency of the L-M algorithm.