From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,FREEMAIL_FROM autolearn=unavailable autolearn_force=no version=3.4.4 X-Received: by 2002:ac8:66d2:: with SMTP id m18mr13404579qtp.302.1589751019209; Sun, 17 May 2020 14:30:19 -0700 (PDT) X-Received: by 2002:a4a:d355:: with SMTP id d21mr10564041oos.66.1589751018908; Sun, 17 May 2020 14:30:18 -0700 (PDT) Path: eternal-september.org!reader01.eternal-september.org!feeder.eternal-september.org!news.gegeweb.eu!gegeweb.org!usenet-fr.net!proxad.net!feeder1-2.proxad.net!209.85.160.216.MISMATCH!news-out.google.com!nntp.google.com!postnews.google.com!google-groups.googlegroups.com!not-for-mail Newsgroups: comp.lang.ada Date: Sun, 17 May 2020 14:30:18 -0700 (PDT) In-Reply-To: Complaints-To: groups-abuse@google.com Injection-Info: google-groups.googlegroups.com; posting-host=47.185.215.60; posting-account=zwxLlwoAAAChLBU7oraRzNDnqQYkYbpo NNTP-Posting-Host: 47.185.215.60 References: <3baf4a73-aae7-4f99-9786-ba5153118c81@googlegroups.com> <1ab5756b-81d8-4b2f-80ff-feeca5270903@googlegroups.com> User-Agent: G2/1.0 MIME-Version: 1.0 Message-ID: <4f80c5bd-0ad0-48ce-b187-c56a79e5e3b0@googlegroups.com> Subject: Re: Not to incite a language war but apparently the Corona lockdown was based on 13 year old undocumented C-Code From: Optikos Injection-Date: Sun, 17 May 2020 21:30:19 +0000 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Xref: reader01.eternal-september.org comp.lang.ada:58721 Date: 2020-05-17T14:30:18-07:00 List-Id: On Sunday, May 17, 2020 at 2:20:56 PM UTC-5, Niklas Holsti wrote: > On 2020-05-17 20:38, Optikos wrote: >=20 > ... >=20 > > Despite your best efforts to side track the issue, we are trying to > > discuss topics that would be applicable to Anatoly's new Ada model, > > so that his doesn't have the same defects as Ferguson's. >=20 > ... >=20 > > We don't need to discuss never-ending wispy cloud formations of > > what-if Ada code in our imaginations anymore. We have Anatoly's > > extant source code to review and suggest improvements upon. > Fine, I'm not preventing you from doing that. But Anatoly's program is=20 > based on very different modelling principles and computational methods,= =20 > so any comparison to Ferguson's code will hardly illuminate the C-vs-Ada= =20 > aspects any more than comparing any chosen C code to any chosen Ada=20 > code, solving different problems. >=20 > >> 3. Whether the epidemiological models and assumptions of Ferguson's > >> group are correct > >=20 > > You keep basing so many of your pronouncements on a one-size-fits-all > > monolithic definition of correctness (and that Ferguson is definitely > > in possession of that One True And Only Correctness=E2=93=87). > That is a false claim. I have never claimed to know anything about the=20 > correctness of Ferguson's models. On this and the bulk of all of your replies on this posting, methinks you d= oth protest too much. Obviously, you are intentionally trying to stifle fr= ee and open debate on this topic. Only you can divulge why you do that. As to your demonstrably false claim that you never made any claims at all a= bout the correctness or validity of Ferguson's model or its design beyond i= ts implementation in C/C++ source code, let's review your prior postings ab= ove: On Wednesday, May 13, 2020 at 9:05:50 AM UTC-5, Niklas Holsti wrote: > On 2020-05-13 16:52, Optikos wrote: > > On which date did they fix the problem? Before or after governments > > acted on the miscalculations? >=20 > There has been no demonstration that the early predictions from this=20 > program, that prodded governments into action, were "miscalculations" to= =20 > any significant degree, especially after the recommended practice of=20 > performing several runs and considering the ensemble of results. That is a judgement not only of the correctness of the source code itself, = but also that the model produces results that are not miscalculations/over-= estimates that are trustworthy enough to be actionable by governments that = were prodded into action by those trustworthy results. On Tuesday, May 12, 2020 at 5:20:14 PM UTC-5, Niklas Holsti wrote: > On 2020-05-13 0:27, Jeffrey R. Carter wrote: > > This is different from the kind of non-determinism of simulations > > that are intended to be run many times with different RNG seeds. >=20 > Yes indeed, and I would not call that non-determinism of the code. The=20 > reviewer also condemned that kind of stochastic exploration and seemed=20 > to confuse it with real non-determinism. It is true that Monte Carlo is= =20 > often used when the system being simulated is chaotic in some way so=20 > that its behaviour is essentially unpredictable, and can be so sensitive= =20 > that no practical floating-point precision can give a truly reliable end= =20 > result in any given simulation. That is another judgement-of-validity on Ferguson's choice of stochastic mo= del's algorithm itself*, not its implementation in source code. The review= er is discussing primarily the design and by cascading ramification the imp= lementation too by using the code as a proxy for a missing design document,= but your defense quoted above discusses not so much the source code, but t= he stochastic algorithm itself as Ferguson's valid modeling design decision= . * that would apply to implementing that design in any other language On Monday, May 11, 2020 at 3:27:06 PM UTC-5, Niklas Holsti wrote: > On 2020-05-11 21:49, Rick Newbie wrote: > > I want to share this article here before it gets buried in the memory h= ole > > https://chrisvoncsefalvay.com/2020/05/09/imperial-covid-model/ >=20 > =E2=80=A6 >=20 > - The authors of the code defended the non-determinism by saying that=20 > the simulation is statistical, anyway, and that all simulations should=20 > be repeated several times to get an ensemble of possible behaviour. The= =20 > reviewer did not accept this defense, but insisted on determinism.=20 > However, I know of at least one example where non-determinism is=20 > accepted and used in this way: simulations of many-body gravitational=20 > systems, such as planetary systems, where it is very common to compute=20 > thousands or millions of simulations and then estimate the likelihood of= =20 > particular final outcomes (say, the ejection of one planet from the=20 > system) from the ensemble of simulations. That is yet another judgement-of-validity on the non-determinism in Ferguso= n's choice of algorithmic design* of the model, not the source code itself. * that would apply to implementing that design in any other language