Hi all, The Intel fortran compiler has a switch - fp-strict that switches off numerical optimization. See also https://software.intel.com/sites/default/files/comment/1721462/03-fp-consistency-2012.pdf
Op ma 18 nov. 2019 18:42 schreef Leonid Gibiansky <lgibian...@quantpharm.com >: > 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 > > > > > > > >
