[R-sig-ME] nlme question...

[Doran, Harold]

This is confusing. First, how is your model non-linear? It looks like it is linear in the parameters. A design matrix is known and parameters are estimated. So, is k known or is it part of the parameters to be estimated. 

Moreover, can you use lmer and not lme since nlme is not supported much anymore

-----Original Message-----
From: r-sig-mixed-models-bounces at r-project.org [mailto:r-sig-mixed-models-bounces at r-project.org] On Behalf Of Jeffrey Harring
Sent: Monday, August 30, 2010 1:48 PM
To: r-sig-mixed-models at r-project.org
Subject: [R-sig-ME] nlme question...

  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

_______________________________________________
R-sig-mixed-models at r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-sig-mixed-models