Re: [FORGED] RE: question about random seed for simulation

On Mar 9, 2017, at 6:34 PM, Nick Holford <[email protected]<mailto:[email protected]>> wrote: Penny, A simple solution using NONMEM is to put the different designs one after the other and separate them with an EVID=4 data item on the first dosing record for each design. You can a DESIGN data item value for each design which then makes it simple to use the simulated data in a subsequent NONMEM estimation run using ACCEPT or IGNORE on the $DATA record. That way you can do the simulation just once and be sure to have all the random effects (ETA) identical for each subject. Best wishes, Nick On 10-Mar-17 12:11, Faelens, Ruben (Belgium) wrote: 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 From: [email protected]<mailto:[email protected]> [mailto:[email protected]] On Behalf Of Zhu, Penny Sent: donderdag 9 maart 2017 19:19 To: [email protected]<mailto:[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 Information in this email and any attachments is confidential and intended solely for the use of the individual(s) to whom it is addressed or otherwise directed. Please note that any views or opinions presented in this email are solely those of the author and do not necessarily represent those of the Company. Finally, the recipient should check this email and any attachments for the presence of viruses. The Company accepts no liability for any damage caused by any virus transmitted by this email. All SGS services are rendered in accordance with the applicable SGS conditions of service available on request and accessible at http://www.sgs.com/en/Terms-and-Conditions.aspx -- Nick Holford, Professor Clinical Pharmacology Dept Pharmacology & Clinical Pharmacology, Bldg 503 Room 302A University of Auckland,85 Park Rd,Private Bag 92019,Auckland,New Zealand office:+64(9)923-6730 mobile:NZ+64(21)46 23 53 FR+33(6)62 32 46 72 email: [email protected]<mailto:[email protected]> http://holford.fmhs.auckland.ac.nz/ http://orcid.org/0000-0002-4031-2514 Read the question, answer the question, attempt all questions