Re: Not to incite a language war but apparently the Corona lockdown was based on 13 year old undocumented C-Code

[Optikos <ZUERCHER_Andreas@outlook.com>]

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 says, 
> > "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 the 
> 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 the 
> 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 only true for multiple cores, but later that was retracted: "But 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 – even in single-threaded mode – 
> > 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 program 
> (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.

On which date did they fix the problem?  Before or after governments acted on the miscalculations?