[R-sig-ME] nlme question...
Jeffrey Harring
harring at umd.edu
Mon Aug 30 19:47:46 CEST 2010
Hi all,
Can the algorithm in nlme handle a nonlinear function that is written as
a design matrix and linear coefficients like the following
The model is a nonlinear growth model with five time points: y = X*b +
e, where design matrix X is defined as
X= | 1 0 |
| 1 1 |
| 1 k |
| 1 2k |
| 1 3k |
and parameter vector b = (b0, b1). And where "k" is a parameter to be
estimated. Of course I also want to estimate the intercept (b0), slope
(b1). Error variances (e) with 5 free parameters and random effects
covariance matrix (2x2: for b0 and b1).
If anyone has concrete suggestions I would love to hear from you.
Thanks for your consideration,
Jeff
--
**********************************************************
Jeffrey R. Harring, Assistant Professor
Department of Measurement, Statistics& Evaluation (EDMS)
1230 Benjamin Building
University of Maryland
College Park, MD 20742-1115
Phone: 301.405.3630
Fax: 301.314.9245
Email: harring at umd.edu
Web: http://www.education.umd.edu/EDMS/fac/Harring/webpage.html
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