RE: [NMusers] hardware question

Dear all,

As Diane Mould states, NONMEM VI is generally more stable than NONMEM V.
However, it has been our experience that, when using a conditional
estimation method, stopping at a local minimum and compiler- and
platform-related differences in termination may occur with NONMEM VI.

Whenever conditional estimation is used, it is prudent to employ
multiple runs with different initial estimates and to repeat runs with
final estimates used as initial estimates in an attempt to detect local
minimums or overall instability.

Tom

-----Original Message-----
From: owner-nmusers_at_globomaxnm.com [mailto:owner-nmusers_at_globomaxnm.com]
On Behalf Of Diane R Mould
Sent: Monday, January 08, 2007 10:43 AM
To: 'Mark Sale - Next Level Solutions'
Cc: nmusers_at_globomaxnm.com
Subject: RE: [NMusers] hardware question

Hi Mark

Yes, clients often want to be able to reproduce a contractor's results
by
re-running the final model on their own system and I would also say that
the
regulators do as well. For Nonmem V, therefore, having different
compilers
and processors is a valid concern. I think Peter Bonate had a poster at
AAPS some years ago investigating differences in hardware and compilers.

However for Nonmem VI, our experience thus far has been that it is not
as
sensitive to compilers and hardware. In fact it also appears to be less
sensitive than Nonmem V was to the run termination status as well (so
even
if the runs terminate, parameter estimates are generally pretty good, as
is
the OBJ), which I think is consistent with what Tom Ludden presented
when he
gave a preview of Nonmem VI. So for your hardware, I would guess if
Nonmem
VI is the system you will be using for future consulting jobs, you
should
not have problems duplicating your results on other hardware.

Good luck finding a buyer :-)

Diane

> -----Original Message-----
> From: owner-nmusers_at_globomaxnm.com
[mailto:owner-nmusers_at_globomaxnm.com]
> On Behalf Of Mark Sale - Next Level Solutions
> Sent: Monday, January 08, 2007 10:18 AM
> Cc: nmusers_at_globomaxnm.com
> Subject: [NMusers] hardware question
>
> For those of you who don't keep track of such things, Intel is, today,
> releasing the desktop (non-gaming) quad core CPU. I'm thinking of
> redoing my entire network, buying maybe 8 quad core machines for the
GA
> application, as well as parallel NONMEM. My question is, as a
> consultant, my clients frequently want to re-run final models on their
> hardware - and I assume that the regulators do as well. How much of a
> problem will it be if I set up my system as 64 bit Vista (or XP) with
> the Intel 64 bit compiler? There will be times when the 64 bit result
> will be different than the 32 bit (as there are times when different
> compiler setting, different compiler etc give different results). Is
> anyone out there planning to move to 64 bit Intel? Will anyone be able
> to rerun my results? It seems, as far as I can tell, the 64 bit system
> is maybe 20-40% faster than a comparable 32 bit system. So, quad
core,
> 64 bit and NONMEM VI (which is faster than NONMEM V), should make a
> noticable difference.
>
>
> Thanks
> (anyone out there want to buy 12 slightly used dual core computers?)
>
> Mark Sale MD
> Next Level Solutions, LLC
> www.NextLevelSolns.com
>
>







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Received on Mon Jan 08 2007 - 12:27:55 EST