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1/0 = 0

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Re: 1/0 = 0

#591

Post by vmchale »

phyzome wrote: post #60

Some people say "oh, that's easy, 1/0 is +Infinity". So the real fun is at 0/0. The limit of x/y as x and y go to zero depends on which path across the xy plane you take towards the singularity. Along one approach, the limit is 0, along another approach the limit diverges to infinity, along yet another the limit is 17. I'm not kidding! Go to https://www.geogebra.org/3d and enter "x/y" and spin the graph around. The "…

Limits aren't the only thing broken by division by zero, though. For integers it's mainly algebraic stuff.

Re: 1/0 = 0

#592

Post by vmchale »

Veedrac wrote: post #230
whack wrote: post #72

My problem with "1/0 = 0" is that it's essentially masking what's almost always a bug in your program. If you have a program that's performing divide-by-zeroes, that's almost surely something you did not intend for. It's a corner case that you failed to anticipate and plan for. And because you didn't plan for it, whatever result you get for 1/0 is almost surely a result that you wouldn't want to have returned to the…

My comment from when this came up on Reddit, slightly edited for context: `/`-by-0 is just an operation and it tautologically has the semantics assigned to it. The question is whether the specific behaviour will cause bugs, and on glance that doesn't sound like it would be the case. Principally, division is normally (best guess) used in cases where the divisor obviously cannot be zero; cases like division by constant…

That's a terrible default for an average function lol. Once again in nearly all cases, taking the average of a list without elements is an error.

Re: 1/0 = 0

#593

Post by vmchale »

nostrademons wrote: post #252
simias wrote: post #183

Earlier quoted context omitted.

I'm reading the "Pony" tweet quoted in TFA and your comment and I'm left very puzzled: is that really that common to want x / 0 == 0 ? In practice where does that crop up? You say that you frequently have to write your little shim but honestly I don't remember writing code like that in recent memory. You talk about progress bars, I suppose it makes sense if you somehow try to copy 0 elements for instance, and you end…

Real example: I'm collecting some quality signals from a corpus, most of which are some form of ratio, average, weighted average, or scaled average of counting various quantities within the documents. If the elements being counted are missing, I want the term involving that quality signal to disappear from the final ranking calculation. Defining x / 0 = 0 gets this behavior for free, while leaving zero as an exceptio…

No, it probably wouldn't, unless you were using integers. Pony still uses floats and returns NaN or Infinity or something.
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