Hi all, in the optim() function there is no control over the size of the initial simplex for the Nelder-Mead algorithm. Two years ago Ben Bolker suggested to include an additional control parameter to allow more flexibility in this respect. Did anybody implement such a modified version. Thanks in advance Jens -- -------------------------------------------- Dr. Jens Schumacher Max-Planck-Institut f. Biogeochemie Winzerlaer Str. 10 D-07745 Jena Germany Tel: +49 (0)3641/576181 Fax: +49 (0)3641/577100 email: jens.schumacher at bgc-jena.mpg.de