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Imperial College London have released their Covid-19 epidemic simulation

github.com

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Re: Imperial College London have released their Covid-19 epidemic simulation

#21

Post by tasogare »

mshook wrote: post #14
notkaiho wrote: post #4

I'm no expert in C++ so not sure if it's meant to look like that, but that code is making my brain hurt.

Just argument parsing makes my eyes bleed... https://github.com/mrc-ide/covid-sim/blob/master/src/CovidSi... That stuff is priceless: else if (argv[i][1] == 'C' && argv[i][2] == 'L' && argv[i][3] == 'P' && argv[i][4] == '1' && argv[i][5] == ':') I guess string comparisons are complicated. I also fail to see why they used ':' as the separator and why they didn't use a proper library to parse argv...

Because when you have only a very limited number of arguments it’s easier to do it that way than selecting a lib, adding it to the project, reading the doc, trying it and integrating it for real. I add the issue in C#, and after trying 2 or 3 libs (including one by Microsoft) I just gave up.

Re: Imperial College London have released their Covid-19 epidemic simulation

#22

Post by asplake »

howd00 wrote: post #12
asplake wrote: post #2

Alumnus here, it’s Imperial College, London. It is a university (in its own right), but always goes by that name.

Only since 2007. Uni of London before that for 100 years. Used to play them at sports as part of the ULU league.

Yes it was part of the University of London, but always “Imperial College”. As far as I’m aware never “Imperial University” as the title initially had it here.

Re: Imperial College London have released their Covid-19 epidemic simulation

#23

Post by JauntyHatAngle »

te_chris wrote: post #16
lbeltrame wrote: post #10

Some people have raised issues with the model[1][2], or rather, the software implementation of it. There's also a (flagged) submission on HN discussing this[3] referencing [1]. [1] (warning: possibly partisan link) https://lockdownsceptics.org/code-review-of-fergusons-model/ [2] https://github.com/mrc-ide/covid-sim/issues/165 [3] https://news.ycombinator.com/item?id=23099212

That issue is unhelpful. Yes, no good tests, but how about suggesting ways it can actually be improved? Why are devs such bores when it comes to things like this? They have released the model, review it and suggest improvements! Don't grandstand "We, the undersigned etc etc" as if that's going to help improve the codebase in the slightest. Carmack is OK with it, he's put his name to reviewing it. That's not to excuse…

I fear that this area is too divisive currently to allow for normal discourse. The downvoting in these kinds of topics have been atrocious on hacker News the last few weeks.

Re: Imperial College London have released their Covid-19 epidemic simulation

#24

Post by gvjddbnvdrbv »

howd00 wrote: post #12
asplake wrote: post #2

Alumnus here, it’s Imperial College, London. It is a university (in its own right), but always goes by that name.

Only since 2007. Uni of London before that for 100 years. Used to play them at sports as part of the ULU league.

Individual colleges were effectively independent universities for many years before. The University of London umbrella was a shell.

Re: Imperial College London have released their Covid-19 epidemic simulation

#26

Post by abainbridge »

JauntyHatAngle wrote: post #19
abainbridge wrote: post #7

This code is great fun. Start here to explore the horror: https://github.com/mrc-ide/covid-sim/blob/master/src/CovidSi... I like the way InitModel() crashes (I think) if a global pointer called bmh (short for bitmap header) isn't first initialized by calling InitBMHead() from Bitmap.cpp. I guess it's obvious to academics with giant brains that InitModel() depends on a bitmap existing. But it gets worse - the pointer…

I appreciate you pointing out the flaws, but I fear they sarcasm is not really warranted. Shit code or not, you can call it out without denigrating the guy. It's nice they aired their source code out for people to look at, least we can do is to critique without snark.

OK, fair point. Snarkiest comment removed. My comments weren't meant to be serious. The problem I pointed out isn't actually a bug, it's just a style of programming that makes the code harder to read/work on than it needs to be.

Re: Imperial College London have released their Covid-19 epidemic simulation

#27

Post by devit »

Is this thing actually being used for policy decisions?

Given the complexity, poor language/framework choice (should have used either Rust or Tensorflow), bad code design, and unclear determination of the parameters (especially the fact they don't seem to be estimated from real data with Bayesian inference, or if they are they didn't release that), as well as the ludicrous CPU and RAM usage making it impossible for most people to run it and thus check it, it doesn't seem like it has any chance of actually being a good model.

If this is the state of the art for the most important statistical modelling project in the world, we are in the dark ages.

Re: Imperial College London have released their Covid-19 epidemic simulation

#29

Post by bencollier49 »

devit wrote: post #27

Is this thing actually being used for policy decisions? Given the complexity, poor language/framework choice (should have used either Rust or Tensorflow), bad code design, and unclear determination of the parameters (especially the fact they don't seem to be estimated from real data with Bayesian inference, or if they are they didn't release that), as well as the ludicrous CPU and RAM usage making it impossible for m…

It's 13+ years old. There was no Rust or Tensorflow when it was originally produced.
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