NMTRAN data truncation

From: "Ludden, Thomas" Subject: [NMusers] NMTRAN data truncation Date: Fri, 19 Apr 2002 13:23:47 -0400 Dear nmusers: The following memo regarding data truncation has been provided by Professor Stuart Beal, The NONMEM Project Group, UCSF. We wish to thank Lynn McFadyen and Nick Holford for bringing this issue to our attention, to Nick for sending us control streams and a modified data file that permited diagnosis of the problem, and to Diane Mould for pointing out that the WIDE option would result in an error message if the number of records exceeded 9999. If you have questions or concerns please contact nmconsult@globomaxnm.com. Tom Ludden Thomas M. Ludden, Ph.D. Vice-President, Pharmacometric R&D GloboMax LLC 7250 Parkway Drive, Suite 430 Hanover, MD 21076 (410) 782-2292 FAX (410) 712-0737 luddent@globomax.com ___________________________________________________________________________ There is a bug in NM-TRAN Version III Level 1.1 (the version accompanying NONMEM version V Level 1.1). It can affect data sets which include clock times. Clock times are transformed to elapsed times in hours for the NON- MEM data set (FDATA). All such elapsed times should have two digits to the right of the decimal point (as with earlier versions of NM-TRAN). With Version III, unpredictably, certain elapsed times greater than 999.99 hours (41.6 days) become mistakenly truncated so that they contain only one digit to the right of the decimal point. Such an elapsed time will be different from what it should have been by up to 5.4 minutes. For many pro- blems, this will not produce a practical difference in the results. However, at the least,it may be an annoyance when with an innocuous change to the NM- TRAN data set (e.g. the dropping of a superfluous data item), some elapsed times become truncated, and there arises a small change to the results. To avoid this, Locate this line in READ3: ELSEIF (VALUE(KK+J).GE.1000.0.AND.WIDE.NE.'Y') THEN Replace with: ELSEIF (VALUE(KK+J).GE.1000.0.AND.WIDE.NE.'Y'.AND.NSP.EQ.1) THEN With this change, one's FDATA file may look different, not only because mistaken truncation will no longer occur, but there may be other changes as well. These changes will have no effect on a NONMEM run. But care should be taken if the FDATA file is used for purposes other than for input to NONMEM. However, there are limits to how large an elapsed time can be in a NONMEM data set created by NM-TRAN. With the above change, an elapsed time can- not be larger than 9999.99 hrs (416.6 days). The following type of message can occur: (DATA ERROR) RECORD 5444, DATA ITEM 5: ******* ELAPSED TIME IS TOO LARGE. USE $DATA ... WIDE This message refers to the option WIDE. With or without the above change, an individual may try to use the option WIDE with a large number of data records and may obtain the message: $DATA: WIDE CANNOT BE USED - FILE CONTAINS MORE THAN 9999 RECS. If it is necessary to use the WIDE option with more than 9999 records, simply locate and delete the following statement in READF: IF (INOBS.GT.9999.AND.WIDE.EQ.'Y') CALL ERRMSG(283,' ',1) and then rerun NM-TRAN. As always after source code has been changed, it must be recompiled. See the Installation Guide.

From: Nick Holford Subject: Re: [NMusers] NMTRAN data truncation Date: Sat, 20 Apr 2002 12:04:54 +1200 Tom, Thanks for posting these 2 suggestions for modifications to NM-TRAN. I have implemented the change to READ3 and can confirm that it fixes the date truncation issue in the data set I had used to identify this bug. I have also implemented the second change in READF but I am puzzled by it. If this removes the restriction on having more than 9999 records with the WIDE option why was the restriction ever there in the first place? Am I correct in thinking that deletion of this line had no other effect except to remove the original arbitrary restriction documented in NMHELP? -- Nick Holford, Divn Pharmacology & Clinical Pharmacology University of Auckland, 85 Park Rd, Private Bag 92019, Auckland, New Zealand email:n.holford@auckland.ac.nz tel:+64(9)373-7599x6730 fax:373-7556 http://www.phm.auckland.ac.nz/Staff/NHolford/nholford.htm *******