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:a37:84c5:: with SMTP id g188mr1119107qkd.344.1589396307842; Wed, 13 May 2020 11:58:27 -0700 (PDT) X-Received: by 2002:a05:6830:2439:: with SMTP id k25mr685347ots.76.1589396307411; Wed, 13 May 2020 11:58:27 -0700 (PDT) Path: eternal-september.org!reader01.eternal-september.org!feeder.eternal-september.org!aioe.org!peer03.ams4!peer.am4.highwinds-media.com!peer01.iad!feed-me.highwinds-media.com!news.highwinds-media.com!news-out.google.com!nntp.google.com!postnews.google.com!google-groups.googlegroups.com!not-for-mail Newsgroups: comp.lang.ada Date: Wed, 13 May 2020 11:58:27 -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: User-Agent: G2/1.0 MIME-Version: 1.0 Message-ID: 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: Wed, 13 May 2020 18:58:27 +0000 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Received-Bytes: 4813 X-Received-Body-CRC: 1557562041 Xref: reader01.eternal-september.org comp.lang.ada:58682 Date: 2020-05-13T11:58:27-07:00 List-Id: On Wednesday, May 13, 2020 at 9:05:50 AM UTC-5, Niklas Holsti wrote: > On 2020-05-13 16:52, Optikos wrote: > > On Wednesday, May 13, 2020 at 4:36:15 AM UTC-5, Niklas Holsti wrote: > >> On 2020-05-13 1:39, Jeffrey R. Carter wrote: > >>> On 5/13/20 12:20 AM, Niklas Holsti wrote: > >>>> > >>>> I agree that it would be troubling. If you could find that statement= , > >>>> it would interest me. > >>> > >>> In https://lockdownsceptics.org/code-review-of-fergusons-model/ it sa= ys, > >>> "the code produces critically different results, even for identical > >>> starting seeds and parameters." > >> > >> While the review claims that as a general flaw, it then "illustrates" > >> the claim by discussing the two cases I detailed, in particular the > >> unexpected influence of the option controlling how the program "stores > >> data tables". This was eventually traced to a difference in the way th= e > >> program used the RNG, depending on this option, which then led to > >> different PRN sequences, depending on this option. An error in the > >> program, of course, but not non-determinism. > >> > >> For programs that use RNGs to drive simulations, a single extra RNG > >> call, or a single omitted RNG call, will completely change the > >> subsequent PRN sequence. This has no effect on the statistical > >> properties of the results from many runs, but will of course change th= e > >> results of the particular run in which the change occurs. > >> > >>> Initially it was claimed that this was > >>> only true for multiple cores, but later that was retracted: "But > >>> Edinburgh came back and reported that =E2=80=93 even in single-thread= ed mode =E2=80=93 > >>> they still see the problem." > >> > >> It seems that some users (Edinburgh) reported that the results varied, > >> and reported they were using multi-core mode. The authors of the progr= am > >> (Imperial) replied that result variations are expected in multi-core > >> mode; this was of course a sloppy analysis of the problem, but not an > >> unnatural one. When the users reported that the problem occurs also in > >> single-core mode, depending on the "data table storage" option, the > >> authors found and fixed the error. > >=20 > > 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. https://www.cato.org/blog/how-one-model-simulated-22-million-us-deaths-covi= d-19 https://www.spectator.co.uk/article/six-questions-that-neil-ferguson-should= -be-asked/amp 2.2 million deaths in the USA and a half million deaths in the UK due to Co= vid-19 (reprising Neil Ferguson's prior years of off-by-orders-of-magnitude= analogous sensationalism that turned out to be wholesale inaccurate in Mad= Cow, H1N1, H5N1, foot & mouth disease) were not a miscalculation, but rath= er a perfectly accurate calculation. Okey dokey, then.