Dear All,
I would like to model my data log transformed.
So far, I already found some suggestions for this problem here but none of
them worked in my case - probably I did sth. wrong.
I would be very happy if someone could help me with changing my error model,
which I assume has to be changed.
(I also assume that the dataset has to be changed from DV to LOG(DV)?)
So, here is the code I used so far (not log transformed):
$ERROR
IPRED = F ;IPRED drug in
the central compartment
IF (CMT.EQ.5) IPRED = A(5) ;IPRED second drug in 5th
compartment
DEL=0
IF (IPRED.EQ.0) DEL=0.0001
W = F
IRES = DV - IPRED
IWRES = IRES /(W + DEL)
Y = IPRED + IPRED * EPS(1) ; error drug in
the central compartment
IF (CMT.EQ.5) Y = IPRED + IPRED * EPS(2) ; error second drug in 5th
compartment
It would be great to get some help.
Thanks!
Katrin
$Error log transformed
Hi Katrin,
You'll have to take the natural logarithm of your DVs
I would change your error block to:
$ERROR
IPRED=LOG(F+1E-16) ; Protection against LOG(0) in case of dosing events etc
Y=IPRED+ERR(1) ; FOR PROPORTIAL ERROR
Cheers!
Rob
Quoted reply history
Van: owner-nmusers_at_globomaxnm.com [mailto:owner-nmusers_at_globomaxnm.com] Namens Katrin Volz
Verzonden: vrijdag 16 december 2016 10:35
Aan: nmusers_at_globomaxnm.com
Onderwerp: [NMusers] $Error log transformed
Dear All,
I would like to model my data log transformed.
So far, I already found some suggestions for this problem here but none of them worked in my case - probably I did sth. wrong.
I would be very happy if someone could help me with changing my error model, which I assume has to be changed.
(I also assume that the dataset has to be changed from DV to LOG(DV)?)
So, here is the code I used so far (not log transformed):
$ERROR
IPRED = F ;IPRED drug in the central compartment
IF (CMT.EQ.5) IPRED = A(5) ;IPRED second drug in 5th compartment
DEL=0
IF (IPRED.EQ.0) DEL=0.0001
W = F
IRES = DV - IPRED
IWRES = IRES /(W + DEL)
Y = IPRED + IPRED * EPS(1) ; error drug in the central compartment
IF (CMT.EQ.5) Y = IPRED + IPRED * EPS(2) ; error second drug in 5th compartment
It would be great to get some help.
Thanks!
Katrin
Het Radboudumc staat geregistreerd bij de Kamer van Koophandel in het handelsregister onder nummer 41055629.
The Radboud university medical center is listed in the Commercial Register of the Chamber of Commerce under file number 41055629.
Hi Katrin,
You'll have to take the natural logarithm of your DVs
I would change your error block to:
$ERROR
IPRED=LOG(F+1E-16) ; Protection against LOG(0) in case of dosing events etc
Y=IPRED+ERR(1) ; FOR PROPORTIAL ERROR
Cheers!
Rob
Quoted reply history
Van: [email protected] [mailto:[email protected]] Namens
Katrin Volz
Verzonden: vrijdag 16 december 2016 10:35
Aan: [email protected]
Onderwerp: [NMusers] $Error log transformed
Dear All,
I would like to model my data log transformed.
So far, I already found some suggestions for this problem here but none of them
worked in my case - probably I did sth. wrong.
I would be very happy if someone could help me with changing my error model,
which I assume has to be changed.
(I also assume that the dataset has to be changed from DV to LOG(DV)?)
So, here is the code I used so far (not log transformed):
$ERROR
IPRED = F ;IPRED drug in the
central compartment
IF (CMT.EQ.5) IPRED = A(5) ;IPRED second drug in 5th compartment
DEL=0
IF (IPRED.EQ.0) DEL=0.0001
W = F
IRES = DV - IPRED
IWRES = IRES /(W + DEL)
Y = IPRED + IPRED * EPS(1) ; error drug in the
central compartment
IF (CMT.EQ.5) Y = IPRED + IPRED * EPS(2) ; error second drug in 5th
compartment
It would be great to get some help.
Thanks!
Katrin
Het Radboudumc staat geregistreerd bij de Kamer van Koophandel in het
handelsregister onder nummer 41055629.
The Radboud university medical center is listed in the Commercial Register of
the Chamber of Commerce under file number 41055629.
Hi,
This problem was discussed before on NMUSERS, here's a link with code
suggested by Leonid Gibiansky and Mats Karlsson (code allowing for a
combined - additive and proportional error in log space):
http://www.cognigencorp.com/nonmem/nm/98may202004.html
You model the log transformed data - so the DV is actually log
concentration. You estimate in linear space and log transform the estimated
concentrations when you define the Y as in the code in the link above.
Regards,
Andrzej
Andrzej Bienczak
MSc, MPharm, DiplPharm
Pharmacometrics Group
Division of Clinical Pharmacology
Department of Medicine
University of Cape Town
K45 Old Main Building
Groote Schuur Hospital
Observatory, Cape Town
7925 South Africa
phone: +27 21 650 4861
mobile: +27 839 842 675
email: [email protected] <mailto:[email protected]>
Quoted reply history
From: [email protected] [mailto:[email protected]] On
Behalf Of Katrin Volz
Sent: 16 December 2016 11:35 AM
To: [email protected]
Subject: [NMusers] $Error log transformed
Dear All,
I would like to model my data log transformed.
So far, I already found some suggestions for this problem here but none of
them worked in my case - probably I did sth. wrong.
I would be very happy if someone could help me with changing my error model,
which I assume has to be changed.
(I also assume that the dataset has to be changed from DV to LOG(DV)?)
So, here is the code I used so far (not log transformed):
$ERROR
IPRED = F ;IPRED drug in
the central compartment
IF (CMT.EQ.5) IPRED = A(5) ;IPRED second drug in 5th
compartment
DEL=0
IF (IPRED.EQ.0) DEL=0.0001
W = F
IRES = DV - IPRED
IWRES = IRES /(W + DEL)
Y = IPRED + IPRED * EPS(1) ; error drug in
the central compartment
IF (CMT.EQ.5) Y = IPRED + IPRED * EPS(2) ; error second drug in 5th
compartment
It would be great to get some help.
Thanks!
Katrin