Re^3: Challenge: Simple algorithm for continuing series of integers

[TimToady]

It would be relatively easy to make a rule that new guessers are allowed to work only on the unguessable residue left over from previous versions. And of course, there's little reason to install guessers that would be opaque to most readers, and I expect that the writer of the program should certainly name the series or the generator function such that it is clear to the reader.

So actually, I was serious in my proposal that we make it easy to pull well-named generator functions from a well-known database, and then the numbers on the front are just examples of the first few values in the series--the real meat is in the function name. But a name is a useful abstraction, compared to forcing people to write complicated closures that might be just as unreadable as * is. And the standard function derived in a standard fashion may well be more optimizable than the user-written equivalent, where various idiosyncratic usages may make optimization difficult.

So that's why the spec currently limits * guessing to some very simple cases, and I have no problem with taking a very conservative approach to adding more guessers.

[BrowserUk]

compared to forcing people to write complicated closures that might be just as unreadable as * is. ... the spec currently limits * guessing to some very simple cases

If the guesser is limited to simple cases, then the closures it would replace, would be simple also. By the time you get to the point where the closure would give any reasonably competent programmer a problem to understand, the chances of the guesser, guessing correctly are close to nil.

Even the simplest input to the guesser, say: 1,2,3 currently elicits a gnat's genitalia off of 13,000 matches at the OEIS.

Adding a fourth term 4 cuts that to 5,500; a fifth gets you 3,500; a 6th, 2,500; a 7th, 2,000; an 8th 2,000. And you're still close to 1,500 by the time you have specified the first 9 terms.

I didn't keep going to see how many leads you'd have to specify to uniquely identify even this simplest of sequences, but I tried a few others:

1. 1,4,9,16,25 - 125 possibles.
2. 1,2,4,8,16 - 346 possibles.
3. 1,3,5,7,9 - 233 possibles.
4. 2,4,6,8,10 - 213 possibles.
5. 1,10,100,1000 - 36 possibles.

It's frankly hard to see the win from having a "simple" guesser. And hard to see the possibility of something more accurate.

Especially when it would be so cheap and simple to provide the top ten or 100 most common sequences named as built-ins, or in a core module.