RE: question about random seed for simulation
Hi Penny,
Nonmem indeed calculates each subject one after the other. The random values
will therefore change. Maybe you can set the random seed every time you
simulate t=0, based on the subject ID?
This may also depend on your data file; have you tried ordering on time (so the
first 50 rows are all t=0 for subject 1 to 50) ?
This largely depends on the simulation software and its design:
As an example: Simulo samples all subjects together at simulation start, after
which it runs the trial design; so the same subjects are sampled independent of
subsequent trial design.
I do not know about other tools (TS.2, simulx, mrgsolve), maybe the authors of
these tools can specify?
Kind regards,
Ruben Faelens
Quoted reply history
From: [email protected] [mailto:[email protected]] On
Behalf Of Zhu, Penny
Sent: donderdag 9 maart 2017 19:19
To: [email protected]
Subject: [NMusers] question about random seed for simulation
Dear All
I have finished a multiple dose simulation for 600 subjects and want to perform
a single dose simulation (different sampling time) on the same subjects (same
ETA as the first simulation). I used the same seed for the simulation step, it
turned out the first subject was the same and the rest of the subjects are not
and I am not sure whether this was due to the fact that the two simulation has
different number TIME records. If so, I wonder what is the proper way to set
the simulation seed so that the ETAs for the second simulation will be
identical to the first one.
I know that I could output the individual parameter estimate from the first
simulation and import them into the second one. But I was thinking if the
random seed can be synchronized between the two simulation, it could be an
easier solution.
Your help is very much appreciated!
Thank you very much and best regards!
Penny (Peijuan) Zhu, Ph.D.
Associate Director Clinical Pharmacology
Cell: 862-926-9079
PD Bio-Pharma CDMA
Sandoz
1N025, 100 College Road West
Princeton, NJ 08540
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