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RE: [NMusers] Use of ACCEPT in $DATA

From: Leonov, Sergei <Sergei.Leonov_at_iconplc.com>
Date: Thu, 24 Aug 2017 23:25:36 +0000

Hi Dennis,

Unfortunately, my reply will not provide a solution to your problem. It is more about drawing attention to the fact that checking conditions numerically is not exactly the same as checking conditions on a piece of a paper, because of rounding. I’m sure that the users of the List are well aware of this fact, just a reminder…

A simple example, I did this in Matlab, you can repeat it in R or other programming language. I won’t waste your time by describing how I came to this example. Compare the output of two expressions:
>> a1=0.06;
>> a2=0.05 + 0.01;

You would expect the equality between the two values, a1 and a2, right? True, on paper. Here is the output of these two values with 20 decimals.
>> fprintf('%22.20f\n',a1)
0.05999999999999999800
>> fprintf('%22.20f\n',a2)
0.06000000000000000500
And, of course, the output of the logical expression (a1 ==a2) is FALSE.

Regards,
Sergei Leonov
ICON Innovation Center

From: owner-nmusers_at_globomaxnm.com [mailto:owner-nmusers_at_globomaxnm.com] On Behalf Of Bill Denney
Sent: Thursday, August 24, 2017 6:45 PM
To: Dennis Fisher; nmusers_at_globomaxnm.com
Subject: RE: [NMusers] Use of ACCEPT in $DATA

Hi Dennis,

I don’t have an elegant solution for you (and I’ve been pining for the use of combined Boolean operations like “TIME.GT.5.9.AND.TIME.LT.6.1” for a long time).

An inelegant solution could be to run the model once with a write statement to see if you can identify the value like 6.0000001 and use it. That would probably be fragile to different processor/compiler/math library combinations, so I’d probably end up making the additional indicator column for certainty.

Thanks,

Bill

From: owner-nmusers_at_globomaxnm.com<mailto:owner-nmusers_at_globomaxnm.com> [mailto:owner-nmusers_at_globomaxnm.com<mailto:owner-nmusers_at_globomaxnm.com>] On Behalf Of Dennis Fisher
Sent: Thursday, August 24, 2017 6:16 PM
To: nmusers_at_globomaxnm.com<mailto:nmusers_at_globomaxnm.com>
Subject: [NMusers] Use of ACCEPT in $DATA

NONMEM 7.4.1

Colleagues

I am trying to use the ACCEPT option in $DATA in order to select a subset of records (to evaluate the impact of the # of samples/subject on confidence intervals).

I used the following code:
               ACCEPT=(TIME=0, TIME=1, TIME=2, TIME=4, TIME=6, TIME=24)

NMTRAN then creates a dataset but — to my surprise — TIME=6 is not in the dataset (all the others are).

I am copying the first few rows of the input dataset so that you can see what is being provided to NMTRAN:

ID,AGE,MONTHS,SEX,WT,AMT,RATE,TIME,EVID,MDV,REPLICATE,IPRED,CWRES,DV,PRED,RES,WRES
1101,12,144,1,30.054,210.38,841.51,0,1,1,1,0,0,0,0,0,0
1101,12,144,1,30.054,0,0,1,0,0,1,187.42,0,179.28,199.26,-19.979,0
1101,12,144,1,30.054,0,0,2,0,0,1,180.92,0,187.92,194.09,-6.1659,0
1101,12,144,1,30.054,0,0,4,0,0,1,169.84,0,177.66,184.37,-6.712,0
1101,12,144,1,30.054,0,0,6,0,0,1,160.61,0,153.43,175.39,-21.96,0

The underlined / boldfaced value (6) in the final row is the problem.

I assume that NMTRAN is reading that value as something other than 6.0 (e.g., 6.000001) and thereby omitting it.

I have reviewed NMHELP to see if there is some other way to accomplish this. Ideally, there would be something like:
               TIME.GT.5.9.AND.TIME.LT.6.1
but that does not appear to be supported.

The alternative is to modify the dataset to include many possible MDV/EVID columns. However, it would be more elegant to do this in the control stream.
Or, if there is some way to find out the exact value that NMTRAN sees, I could specify that value.

Any help would be appreciated.

Dennis

Dennis Fisher MD
P < (The "P Less Than" Company)
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Received on Thu Aug 24 2017 - 19:25:36 EDT

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