Dear Yousef, You may see if you find some recent work of Chunming Zhang (e.g., in Annals of Statistics, vol. 36, 2008, 1693--1725; Computational Statistics and Data Analysis, vol. 52, 2008, 4859--4871) useful. These work are based on use of semiparametric methods. You may find these papers at http://www.stat.wisc.edu/~cmzhang With regards, S. Purkayastha. On 6/12/09, marefat <[log in to unmask]> wrote: Hi All: Is it possible to perform non-linear regression with SPM? Are there any extensions that have been implemented that could be used for this application? Thank you Yousef -- ----------------------------------------------------------------- Sumitra Purkayastha Associate Professor Bayesian and Interdisciplinary Research Unit Indian Statistical Institute 203 B.T. Road. Kolkata 700 108. INDIA Tel: +91-33-2575 3406 (office) Fax: +91-33-2578 5260, +91-33-2577 6925 -----------------------------------------------------------------