Thanks Bob and Peter!
The model is quite stable, but this is LAPLACIAN, so requires second
derivatives. At iteration 0, gradients differ by about 50 to 100%
between Intel and AMD. This leads to differences in minimization path,
and slightly different results. Not that different to change the
recommended dose, but sufficiently different to notice (OF difference of
6 points; 50% more model evaluations to get to convergence).
Thanks
Leonid
On 11/18/2019 12:15 PM, Bonate, Peter wrote:
Leonid - when you say different. What do you mean? Fixed effect and random
effects? Different OFV?
We did a poster at AAPS a decade or so ago comparing results across different
platforms using the same data and model. We got different results on the
standard errors (which related to matrix inversion and how those are done using
software-hardware configurations). And with overparameterized models we got
different error messages - some platforms converged with no problem while some
did not converge and gave R matrix singularity.
Did your problems go beyond this?
pete
Peter Bonate, PhD
Executive Director
Pharmacokinetics, Modeling, and Simulation
Astellas
1 Astellas Way, N3.158
Northbrook, IL 60062
peter.bon...@astellas.com
(224) 205-5855
Details are irrelevant in terms of decision making - Joe Biden.
-----Original Message-----
From: owner-nmus...@globomaxnm.com <owner-nmus...@globomaxnm.com> On Behalf Of
Leonid Gibiansky
Sent: Monday, November 18, 2019 11:05 AM
To: nmusers <nmusers@globomaxnm.com>
Subject: [NMusers] AMD vs Intel
Dear All,
I am testing the new Epyc processors from AMD (comparing with Intel Xeon), and
getting different results. Just wondering whether anybody faced the problem of
differences between AMD and Intel processors and knows how to solve it. I am
using Intel compiler but ready to switch to gfortran or anything else if this
would help to get identical results.
There were reports of Intel slowing the AMD execution in the past, but in my
tests, speed is comparable but the results differ.
Thanks
Leonid
