1. Nlmix: A Program for Maximum Likelihood Estimation of the Nonlinear Mixed Effects Model with a Smooth Random Effects Density. Nlmix is a program to estimate the fixed parameters of the nonlinear mixed effects model and the density of the random effects jointly by maximum likelihood. The density of the random effects is assumed to be smooth but is otherwise unrestricted. The method uses a series expansion that follows from the smoothness assumption to represent the density and quadrature to compute the likelihood. Simulation from this representation is easy and may be used as an alternative to quadrature. Standard algorithms are used for optimization. Empirical Bayes estimates of random coefficients are obtained by computing posterior modes. Copyright (C) 1991 by Marie Davidian & A. Ronald Gallant. Permission to use, copy, modify, and distribute this software and its documentation for any purpose and without fee is hereby granted, provided that the above copyright notice appear in all copies and that both that copyright notice and this permission notice appear in supporting documentation. This software is provided "as is" without any expressed or implied warranty. 2. The nlmix source code is in directory pub/arg/nlmix/code. 3. The Nlmix Users Guide, in PostScript, is file nlmix.ps in directory pub/arg/nlmix/guide. 4. Nlmix uses the optimizer NPSOL. We have been granted permission to distribute NPSOL code in connection with distribution of SNP, a program for nonparametric time series analysis. As nlmix is layered on top of the SNP code, which is included in the distribution of nlmix, we may distribute in connection with nlmix. See directory pub/arg/nlmix/npsol There is no charge but your institution will be required to honor the license agreement. 5. There is a machine dependent parameter eps in the files gaussq.f, mcarlo.f, normalh.f, plot.f, post.f, and quad.f that are set for an IEEE machine, such as a Sun SparcStation2, and will need to be changed for machines that do not use IEEE floats. 6. nlmix.tar can be unpacked by using unzip on Microsoft Windows or tar -xf nlmix.tar on a Unix machine.