From: "Rajeev Menon" 
Subject: [NMusers] Log-transformation
Date: Fri, 10 May 2002 13:45:22 -0400

Hello All,

I was trying to do a log-transformation. My error statement was

Y=LOG(F) + ERR(1)

I get the following message when I try to run this

runtime error M6202: MATH

- log: SING error

Image    PC      Routine
nonmem.exe 0043F049 Unknown
nonmem.exe 0043EE7B Unknown
nonmem.exe 0043D878 Unknown

Could anyone please tell me the best approach to overcome this.


Rajeev Menon, Ph.D. 
 PPD Development
 Clinical Pharmacology


From: "Bachman, William" 
Subject: RE: [NMusers] Log-transformation
Date: Fri, 10 May 2002 13:52:32 -0400

You are probably trying to take the log of zero.  You need to protect the
code for the points where F=0.



From:  "Venkatesh Atul Bhattaram" 
Subject: Re: [NMusers] Log-transformation
Date: Fri, 10 May 2002 14:46:23 -0400

 Hello Rajeev

You will need to include these in your error model.


IPRED = -3 

IF(F.GT.0) IPRED = LOG(F) ; to avoid LOG(0) run-time error 

Y = IPRED + EPS(1)

Venkatesh Atul Bhattaram
Post-doctoral Fellow
University of Florida