Kata

raising as an issue.

Just use round() function returning the results. How can I make it clearer?

I don't know. Should I be maintaining fractional people throughout the process? Or should I be rounding at each day? Because I feel like I should be rounding at each day since fractional people can't be infected. It's a binary state.

You definitely shoudn't round each day, although I can understand why you consider it. Generaly speaking for every single value here we take a mean for thousands of people. Doing it by looking at individuals we should look like this:

• Incubation time: 2-14 days
• Infecting time: 1-20 days Ofc we need to take these numbers randomly, set up weight. That's why it's better to simplify.

Anyway, there is an information that results must be rounded. Should I add any additional information?

You should add precisely what you told me - that fractional people are to be carried forward until the very end and only the returned results are to be rounded. That will inform solutions from the start instead of forcing a complete solution redesign.

Changed to: "In case multiplier is a fraction, round the result numbers only." Is it acceptable?

You're right. There are a lot of terms which should be defined better. As there are many informations, I decided to introduce them step by step. I'm thinking about creating a summary or introduction, just listing those terms. Is it a good idea? Any more suggestion?

I rearanged it a bit, can you take a look?

not sure yet... Seems stuff is still missing.

Like, in the first part, seems to me you're assuming that any people are "at contact" with any other people as long as they aren't confined. Tho, you give the first batch of data without having explained anything about that.

Defining stuff in the beginning sounds good, yes. Even better if you begin giving the general idea about the task first, without any specifics. "We are about to model... the model will take stuff into account..."

Finally, you never give a concrete section explaining either what the inputs look like, or what the actual output look like. => missing those two sections in the description, and an actual example.

To get first batch of data you only need incubation time and infection rate. Once again, can you take a look please?

na, not good enough: now there is a "multiplier" thing showing up in the input example that is never talked about anywhere. x/

• first line, ok. But "need to build", in the second sentence of it.
• then present all the parameters your model will rely on. Just the names and what they mean in the context
• Then you can go with explainations.
• explaining what is the output after the example of actual output is a bad idea... x)
• "days'" should be "duration", I guess
• I'm not sure about this sentence (2nd §): the growth will look like this:... are you absolutely sure you're talking about "growth" here? and not number of people? Because according to the following part, it seems to me you're actually talking about a number of people. No?

Warning, there is a mistake you need to avoid: at that point, fixing the description by patching it here and there may just lead to more mess. Better to summarize what you need, and to reorganize the whole thing, rewritting the description from scratch.

For government and statistics people are not important. The focus is on growth (in case of epidemic exponential growth) :) Jokes aside, I'll change it.

"Finally, you never give a concrete section explaining either what the inputs look like, or what the actual output look like." I understood it as giving input and output. Can you explain it?

I need an hour or two without thinking about it, so I'll lose this description in my mind and I'll be able to create something new. Thank you for your contribution!

I understood it as giving input and output.

yes that's more or less the idea and what you did. You can make it more "concrete" using titles:

## input:

blabla..


## output:

blabla..


## example:

blibli...

I wrote it from the beggining. I guess that means that new errors appear, but hopefully it'll be better this time.

The text is long, with a lot of data, what makes it boring and hard to read. I allowed myself to add some epidemic humor. Please let me know if it's not appropiate or delete/unpublish if I may get banned for it.

'begins to feel better, in there. ;) Still some things to tackle, tho.

• you're presenting the whole thing as something realistic, but there are hidden assumptions in there that do not make it realistic at all. That's not really a problem, but since you rely on concrete examples, those underlying assumptions should be perfectly explicited. Like:
  • for now, you assume all migrants are infected, all at "day 0" in the "disease process". Aside from the fact that the association "migrant==always infected" is quite a dangerous idea to expose/propagate (pun) nowadays (pun, but some could call you racist for that, so... :/ ), this is totally unrealistic. As you can see, in the first line, we already have 2 unrealistic assumptions... :o / About the wording: "entrants"? "foreign visitors"?
  • multiplier: you're assuming (like I said in a previous message) that any people can infect any other people in the whole country => "Be sick at NY, you'll infect a guy at Miami!" => Completely unrealistic too. So needs to be either changed, or told about.
  • active: you're considering that the contagioon is possible only for already sick people. Unrealistic too: contagion can happen before the symptoms are declared. New assumption that you need to explain, or you need to use a better wording somehow. Like, your "incubation time", isn't really the incubation time, but the time before someone infected becomes contagious (this might be a better change to do).
  • infecting time: here this is simply a "clash" with the usual meaning of the word. In realistic terms, I guess this would be the number of days between the beginning of the contagious state and the actual symptoms showing up, so before the isolation of the patient. This is understandable in the current description, but the explaination is currently rather convoluted. Would be better to reword that part to.
  • incubation, infecting and recovery times: looking at those three (note: I din't try to solve your kata for now), it seems to me you're actually using 2 different kind of things, in there. incubation and infecting time seems to be consecutvie durations, while the recovery time seems to be overlapping the two previous. Though, this is not specified, so not clear. => Needs to be reworded or specified (I bet this can be sorted out from the example below, but ease the way for the users: correctly explained problem == happy user)
• death rate: I guess that's one of the puns? x) Well, why not, but worded like that, it doesn't sound like a pun x) (especially like "well, kill 1 out of 10, who bothers?" ;o )
• Same as above for the dog thing.
• On day 3 to 7 Robert is still infecting -> you're talking here about the infecting time while you didn't give/explain it yet (it's given 2 lines below)
• Infecting time = 5, so Robert is spreading... that part comes a bit "out of nowhere". I mean, the "Infecting time = 5". => You're discussing an example, so begin with providing the full set of inputs (-> at the line just after the "epidemiologist" thing) and then, that part will go smoothly.
• there is something that sounds fishy about those numbers... So:
  • incubation=1 day, infecting=5 days
  • day 1: Roger is incubating, ok
  • day 2: he becomes active and starts infecting, ok...
  • now, you say: On day 3 to 7 Robert is still infecting, so: days 2,3,4,5,6,7... That makes an infection time of 6 days, that, not 5. => new assumptions you're doing without telling, or a mistake somewhere?
  • tho the next § seems to tell that he doesn't infect anyone on day 7 because he's isolated, so I guess it's a wording problem, rather.
• ... with Anya, so she is incubating on day 3 and on day 4 she is infecting -> prefere this version: ... with Anya, so she is incubating on day 3 and she is infecting on day 4...

Sorry for the wall of text... XD

But as you can see, even if it's already far better, there are still a lot of things to handle yet. ;)

Cheers

1. Migrants != immigrants. Correct me if I'm wrong. It's not only foreign people, because for example in Poland most of infected people who arrived were Poles who spent winter break in Italy.

2. I changed "migrants" to "infected migrants", that's what I meant.

3. Everything here is an average. Incubation for COVID-19 can last from 2 to 14 days. People will infect shorter or longer. The beauty of this is that if we don't care about individuals, we can take some constant values and make the model much simpler.

4. "any people can infect any other people in the whole country". Yes, again to simplify things. The model still works for the very beggining of epidemic, like first 2 months. As I understand, you want to add SIR model together with containers (infection spreads faster in a container than between them). It's nice and something to think about, together with giving the number of confirmed cases and estimating infected people with incubating virus and more random values. My point was to make this task "as simple as possible" while still talking about incubation time and infecting time.

5. "active: you're considering that the contagioon is possible only for already sick people". Again, to simplify things. Actually it's something I could mention, but I'm not sure where... There are people who are not sick and they're spreading virus. In case of COVID-19 it's around 10%, who will never get sick and they are a huge problem if we try to just isolate people, without making tests.

6. Changed infecting time and recovery time description. Recovery time will be overlaping anyway, just the question is should it overlap the incubation time. I left it as it was.

7. About death rate, we can bother, but 10% while 90% of them are over 60 years old... This part is actually too realistic and I think it's the main reason why many governments didn't want to introduce heavy restrictions straight away. They don't bother.

8. Dogs are unrealistic, it's just a joke with some truth. Noone cares about animals during epidemic. To this day numbers are very small thanks to restrictions and high higiene standards, but if milions of people will be dying, then noone will talk about animals.

9. Anya description changed.

10. The most important one! I clearly made a mistake in script (I can't count to 5). I'll dig deeper to check other values. I don't know why it happened yet, so I'm unpublishing the task.

Thank you for wall of text, very useful :)

1)woops, I'm not english native, surely I'm wrong, here, yes.

3,4,5) that's not really my points. What I'm trying (and apparently failing) to say is that you perfectly can use those approximations, I see nothing wrong about that, but you have to be clear about those. Just be explicit ("we'll considere that, to simplify the problem")

let's see when you comes back from your draft section, so

Cheers.

Apparently the bug was stupid and doesn't affect other parts, so I published it again. Added a note.

One more question... It's my first kata, I would like to know how to make it interesting.
I noticed that even though the problem is interesting, it's hard to present it in interesting way. Plenty of text, many parameters are the biggest issue here - at least I think so. I though that for people who like algorhitms it's a nice task, but it seems I was wrong.

Could you give me a tip, the idea, how would you create a task about epidemic and exponential growth?

Hi

Here, you somehow enter the weird world of personal tastes. There is no real rules. Moreover, the feedback from the very same user can vary from one day to another...

Nothing more useful to say, sorry... :/

Ok, thank you.
Should I consider the problem as resolved, or come here in half a year and try to change it once again?

You need to read docs about markdown lang. CodeWars use a 'modified' version of it, also new lines are handled differently in kata desc and comment part. For simplification, you only need to know that

• Leaving an empty line will create paragraphs
• Add TWO spaces at the end of line will insert a new line

Thank you :)

Thank you for information. I actually thought about making a similar/the same task. This one is different, harder. What is more, his task is completely unrealistic. At least in my mind, my task is a good example how infection spreads at the very beggining of epidemic. Things to understand: people do not infect immediately, both infection rate and infecting time have a huge impact on numbers.