On 10/22/07, Henning Thielemann wrote:

Cute!

+1 http://programming.reddit.com/info/5yuhf/comments/ -- vvv

If someone organized something like that, (or even a more extended version like the ongoing attempts a while back to optimize for the language shootout) I'd be totally in. Seems like a great way for newer foax to take a crack at something useful and interact to get a better handle on the language. --S On Oct 22, 2007, at 10:54 AM, Brent Yorgey wrote:

The Online Encyclopedia of Integer Sequences should really contain more Haskell code for describing the sequences.

Agreed! I propose an "OEIS party" where we all sit around one day and submit Haskell code. =)

(I'm only half joking...)

-Brent _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

Carl Witty wrote:

On Mon, 2007-10-22 at 10:54 -0400, Brent Yorgey wrote: The Online Encyclopedia of Integer Sequences should really contain more Haskell code for describing the sequences.

Agreed! I propose an "OEIS party" where we all sit around one day and submit Haskell code. =)

(I'm only half joking...)

See http://www.sagemath.org/hg/sage-main/file/cf44d55e626b/sage/combinat/sloane_... for the very beginnings of an effort to write OEIS code in Python (for the SAGE computer algebra system). (It looks like currently 130 sequences are implemented.) Maybe this would be useful as a starting point.

This is a bit of a waste of human time, especially since automated methods (like gfun [1]) can automatically find closed-forms for about 1/3 of the sequences on OEIS. Generating code from the output of gfun is an easy task, and leads to rather pretty results [2], in my completely biased opinion. Very very few of the sequences outside of that 1/3 has known "programs" associated with them. Now, using many of Jerzy Karczmarczuk's ideas [3] and Haskell packages, one could rewrite gfun in Haskell, and the end result would likely be extremely elegant, although making it efficient might be rather more challenging. Jacques [1] http://portal.acm.org/citation.cfm?id=178368 and http://algo.inria.fr/libraries/ [2] http://www.cas.mcmaster.ca/~carette/publications/CaretteJanicki.pdf [3] http://users.info.unicaen.fr/~karczma/arpap/

Uh, not quite. My code essentially treats mathematica as a function on strings, (and involves some additional shell wrapping), since there's essentially no processing to do on the Haskell side there. If you wanted to do it right, you'd probably want to write an FFI binding to MathLink. On 22/10/2007, Stefan O'Rear wrote:

On Mon, Oct 22, 2007 at 07:20:47AM -0400, Brent Yorgey wrote:

...

* returning a lazy infinite list for infinite sequences via an embedded general AI and Mathematica interpreter.

Assuming you have a licensed copy of Mathematica, get in touch with Cale Gibbard; he has done all the work for interfacing Mathematica with Haskell (cf 'mbot' on freenode).

Stefan

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On 22/10/2007, Brent Yorgey wrote:

Now, if the OEIS stored *Haskell* code to generate sequences...

-Brent

Yeah, that would be rather nice. :) I think I have seen Haskell code on a few of the entries, even, but I don't know how standard the format is.