Back to the Top
Dear colleagues,
I would appreciate if you could share some of your thoughts on this issue.
I have this user defined model in which I need to call the DTA() function to read through some data. The problem is DTA() doesn't tolerate any missing value in the data column it reads. The model just stopped. Is there anyway to set up a condition statement, something like
if DTA(4)="Missing" then
......
else
my calculation code
endif
Thanks.
Jun Shen
Senior Pharmacokineticist
Seventh Wave Labs
Back to the Top
The following message was posted to: PharmPK
Dear Jun-Shen,
AS I recall the DTA() function in WNL classic (versions 5.x and earlier) is used as an indicator variable.
It's intended use is to give a flag or value that indicates to which set of data the observations belong, therefore I think you should not have missing values here - simply use a number that you do not call in the model and it will be ignored. To set this you could use Transform or preferably multi-transform in a data step preceding your model run.
Alternatively, as a maintenance-paying customer, I would propose you look at your *free* upgrade to Phoenix WinNonlin 6.1 which as well as allowing you to run your old ascii models will give you access to the much enhanced Phoenix Drug Model Engine and the data manipulation enhancements of the Phoenix workflows. You may also seek out tips and discuss Pharsight products with other users at www.pharsight.com/extranet (again free access but a login is required)
Lastly to assist with users upgrade planning please be aware that 6.2 will be due at the end of the year and will support the IVIVC tool kit, AutoPilot as well as some minor general fixes and NLME enhancements. (That said a 'typical' NCA user should be fine with 6.1).
Best regards,
Simon.
--
Simon.Davis.aaa.certara.com
Senior Scientific Consultant
Pharsight- A Certara(tm) Company
Back to the Top
The following message was posted to: PharmPK
I'm not sure of the answer myself, but have you tried asking this
question on the Pharsight Extranet forum? (I'm not a part of Pharsight,
but do use the forum myself)
www.pharsight.com/extranet
Also, you might want to look at Pharsight new Phoenix WinNonLin 6.0
product, I know this has much more extensive modelling capabilities and
might do what you want more easily. (and if you have a current WinNonLin
license you can use it for Phoenix as well, for free)
Regards,
Paul.
--
Paul Hurley
Back to the Top
Hi, Simon/Paul,
Thank you for your replies. Actually inspired by a clue in Simon's reply, I figured it out over the weekend. Allow me to answer my own question.
As Simon mentioned, DTA() is intended to read a flag value. But it is useful to read through a data column to do some user-defined calculation. In my case I use DTA() to calculate observed Cmax, which in turn is used for further calculation. For missing value problem in the data column, we just need to add a new column with indicator values (e.g. 0 for with a value, 1 for missing value), then in the model, we can use a IF-THEN statement to skip reading where the indicator value is 1.
Welcome more comments.
Jun Shen
Senior Pharmacokineticist
Seventh Wave Labs
Want to post a follow-up message on this topic?
If this link does not work with your browser send a follow-up message to PharmPK@boomer.org with "How to skip "Missing" values when calling DTA() function in WinNonlin" as the subject | Support PharmPK by using the |
Copyright 1995-2011 David W. A. Bourne (david@boomer.org)