[seqfan] Re: metadata for Mathematica code

[Charles Greathouse]

Also worth mentioning are the possibility of malformed and even malicious
code. But we never expected a perfect test for functions, in light of
Rice's theorem. It should suffice to give responses "programs are
consistent", "programs are inconsistent", and "I can't tell". I think the
third should be rare enough (< 10%, say) that it doesn't invalidate the
general approach.

I have been doing testing of PARI/GP functions lately, using only ones
following my preferred naming scheme, and I actually haven't had many
problems so far (and I managed to find a decent number of errors, most
minor though).

Charles Greathouse
Analyst/Programmer
Case Western Reserve University

On Thu, Nov 12, 2015 at 4:59 PM, Frank Adams-Watters <franktaw at netscape.net>
wrote:

> Note that comparing terms to a program has a problem: some of the programs
> run much too slowly; the test will never finish. Even for sequences where a
> fast algorithm is known (and hopefully has a function implementing it),
> there may be other programs present that are not efficient. So you can't do
> any sort of automatic scan, nor unconditionally test new programs.
>
> Franklin T. Adams-Watters
>
>
> -----Original Message-----
> From: Charles Greathouse <charles.greathouse at case.edu>
> To: Sequence Fanatics Discussion list <seqfan at list.seqfan.eu>
> Sent: Thu, Nov 12, 2015 12:19 pm
> Subject: [seqfan] Re: metadata for Mathematica code
>
>
> As Eric suggested, I'm very much in favor of doing something along these
> lines.
> It has a number of different benefits: making it easier to see what
> a program
> does, splitting consecutive programs by the same author, etc. But
> more important
> than these, I think, is making it machine-readable. When the
> intent of the
> program is defined unambiguously, it's possible to check
> programs in lots of
> interesting ways:
> * Does the n-th term match the program's TermFunction?
> * Is
> the MembershipTestFunction true for all known terms?
> * Is the
> MembershipTestFunction false for all terms strictly between
> existing terms?
> *
> Does the sequence have a MembershipTestFunction but is nonmonotonic?
> * Does the
> TermListByMaximumFunction act sensibly (e.g.,
> TermListByMaximumFunction[n] is a
> subset of TermListByMaximumFunction[n+1])?
> * Do two programs of the same type
> give the same output?
> etc.
>
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