Bayesian estimation

From: "S.Beal" <stuart@c255.ucsf.edu> Date: Sat, 30 Sep 2000 09:33:25 -0700 (PDT) Dear NM-Users: I want, please, to briefly respond to a recent series of messages over the NM-Users Net, stemming from a question by Dr. Quyen Ho-Ngugen. As has been pointed out already by Dr. Gibiansky and Dr. Sheiner, Dr. Gobburu seemed to have misunderstood the question. Also, Dr. Hiraoka has pointed to some useful earlier information (to be found on the NM-Users Archive) provided by Mrs. Boeckmann. Dr. Gobburu's response, concerning the use of a user-routine called PRIOR (which is in fact not very relevant to Dr. Ho-Ngugen's question), prompted others to make comments concerning this routine. This in turn has prompted me to attempt to communicate the following policy statement. The PRIOR routine is an unsupported feature of NONMEM Version V Level 1.1. No information concerning this feature or any other unsupported feature is available to the greater NONMEM user community from the NONMEM Project Group or from the NONMEM consult group at GloboMax. If you have heard about some feature, but it is not documented (a good place to look is in the Help Guide), the chances are that it is unsupported. NONMEM contains some unsupported and undocumented features. This is done in part to allow us at the NPG to experiment with these features and learn about their use. As our understanding of a feature increases, we usually realize that the feature needs modification. Eventually we may come to feel that it should be made available to everyone in a future release, in some final, supported, and documented form. With other software, this type of "temporary feature" is found only in a beta version of the software. With NONMEM, on occasion we have embedded a temporary feature into our distributed version (currently NONMEM Version V Level 1.1). Perhaps this has not been a good idea, as it can lead to confusion. You may find someone using one of the temporary features in NONMEM Version V Level 1.1 (e.g. PRIOR). This person is either (a) someone working directly with Lewis Sheiner or myself and is helping us test the feature or (b) someone with whom we are not working but who has been able to obtain the help of a person of type (a). Anyone using a temporary feature is obviously running the risk that there is some problem with it, which will be readily discovered with further testing, or that the feature will not "look" or behave the same in a future release. There are also beta versions of future releases. (The distribution of these is handled in a very restricted way; please do not inquire about them.) For those of you who might be using such a release, the chances are quite good that any temporary feature in NONMEM Version 5 Level 1.1 behaves differently with a beta version. Stuart Beal