@zac4code & @g964 ,

Thanks for your replies. And, thanks to the author for the kata. It was substantive work, I'm sure. And it's been stimulating, at the very least. That said, I see that my comments are being inappropriately marked "resolved." That's unfortunate. So, this is the last reply I'll give on the kata, unless I can find a way to report it.

That said, in my example of the study-group, I note the difference between the "perceived" number of students on day-1 (2) and the "abstract" (in my example, I, perhaps unhelpfully, use the word "real") number of students (2.5). While I'm sympathetic to the point that half-students aren't possible, artificially forcing that value to be an integer makes it impossible to express the results—day-0 (1 student), day-1 (2 students), day-2 (4 students)—in a mathematical function.

@g964 , I'm afraid I don't understand your citation of Wikipedia's population-growth charts. And, I've seen the note in the kata's description. Unfortunately, it doesn't communicate what the author hopes it does. While the "clear [?!] hint" is undoubtedly good faith, the reader can't be expected to think the author means "selectively ignore the principles of mathematics." And, I'd argue, they shouldn't have to.

One might say, "Listen, the kata isn't an issue." I think it is. And, even if we assume I'm being pedantic in my adherance to the utility of decimals (a position I'm as surprised as anyone to find myself taking), I'd cite as arguments in my favor everyone coming to the comments saying, in effect, "My code is right, my math is right, but the kata says I'm wrong." The kata does a disservice the community, NOT because it's "tricky," but because it misunderstands math and it uses that misunderstanding to mislead people trying to code into thinking their code is wrong, when it isn't.

Best wishes on your coding,

Cpy on my answer above:

@adamgosnell : you are free to consider that there is an issue but I don't.
The calculation is conform to the different results given by tables about population statistics. See for example:
"Global annual population growth" at https://en.wikipedia.org/wiki/World_population#Annual_population_growth.
Besides that a clear hint is given in the description.

@adamgosnell : you are free to consider that there is an issue but I don't.
The calculation is conform to the different results given by tables about population statistics. See for example:
"Global annual population growth" at https://en.wikipedia.org/wiki/World_population#Annual_population_growth.
Besides that a clear hint is given in the description.
@zac4code : thanks for your explanation and thanks for your thanks.

Users keep asking this question. Perhaps the description of the kata should be updated to state something about this nuance. In fact, all these users ask the right question. There is no good reason to truncate the fractions after each cycle of the runtime (in this case, a year). Depending on the runtime used, different results would be expected, which does not make sense. Anyway, I would add something in the description, rather than changing the kata.

The kata is problematic. I posted about it, but in the meantime, I'd skip it.

Yeah, they're not very clear, here.

Yeah. It doesn't make sense, but that's what's needed.

Sorry no one actually answered your questions. I'm not sure how to report a kata, but I'd be interested to know.

The kata is problematic. I posted about it, but in the meantime, I'd skip it.

[edited]

The kata is problematic. I posted about it, but in the meantime, I'd skip it.

This isn't true. Suppose I have a study group. On day 0, the study group has one student. Suppose it grows at a rate of 1.5 students/day. How many students does it have on day 2? Well, On day 0, it has one student. On day 1, it has two students (but, notice, the "real" value is 2.5). On day 2, it has four students. If we imagine that the decimal values are irrelevant, as the kata does (on the basis that "you can't have half-persons"), the day 2 value would be "three students." But it isn't and it shouldn't be. The value is SUPPOSED to be "four students." What is MEANS that the group grows at a decimal'ed rate is that every 2-days it grows by two students instead of by one.

I'm not sure this makes sense. The note is about percents. The people who are having issues with a single test failing are struggling with percents. They're struggling with the case arguments: [1000 2 50 1214] thinking wrongly about decimals.

The kata is problematic. I posted about it, but in the meantime, I'd skip it.