RE: DV Simulation

From: "Ludden, Thomas" Subject: RE: [NMusers] DV Simulation Date:Thu, 29 May 2003 17:27:32 -0400 In NONMEM V the need for the FORWARD option is a bit complex. That is why I purposely chose to use "may be" instead of the more definite "will be" since I was relying upon distant memory. :-) As Nick pointed out, when there is more than one table file the default is NOFORWARD and the FORWARD option is required for each $TABLE record. However, when only one table record is specified and there are SUBPROBLEMS the tabled items for all subproblems are placed in the single table file without using the FORWARD option. Marc Gastonguay noted this behavior a little over a year ago. The inconsistency will be fixed and the help file updated in version VI. For those who might be interested, there is a bit of history to the way that tables are produced. NONMEM originally produced only one table. Somewhere about version 4 or 5, I believe, it became possible to output up to 10 tables. It appears that there are different sections of Fortran code used for one table (old code) versus more than one table (new code). An inquiry to Professor Stuart Beal yielded the following explanation. ...there are three errors. First, the HELP item for $TABLE talks about FORWARD and NOFORWARD in terms of separate problems. However, the same rules that govern separate problems also govern separate subproblems, and this isn't mentioned. So we'll fix this with HELP Ver VI. Second, the control stream with two $TABLE records runs correctly. This is because, as may be seen in the help item, NOFORWARD is the default. But the error is with the control stream with one $TABLE record. The table should have only the output from the last subproblem. So we'll fix this with Ver VI. Third, the HELP item for $TABLE is incomplete also in that it doesn't mention the following. Within the same (sub)problem, with any sequence of contiguous $TABLE records using the same name with the FILE option, all but the first of the sequence will be treated as though they contain the FORWARD option, even though some may contain NOFORWARD (explicitly), or some may contain neither FORWARD nor NOFORWARD. For to do otherwise, makes no sense. Tom Ludden