Speed

[Peter M. Brigham]

On Aug 26, 2014, at 9:42 AM, Beat Cornaz wrote:

> Works like a charm, Geoff. Great way of tackling the thing, very original.
> 
> function P2 N,B
>  -- N is the depth to permute
>  -- B is the ASCII value to start from
>  -- so P2(1,49) returns 21 cr 12
>  -- P2(2,53) returns 675 cr 765 cr 756 cr 576 cr 657 cr 567
>  if N = 0 then return numToChar(B) & cr
>  put P2(N - 1,B) into T
>  add B to N
>  repeat with i = B to N - 1
>     put T into T2
>     replace numToChar(i) with numToChar(N) in T2
>     replace cr with numToChar(i) & cr in T2
>     put T2 after R
>  end repeat
>  replace cr with numToChar(N) & cr in T
>  return R & T
> end P2
> 
> If I input  B =97 I get the permutations in abcd etc. which I often use, so really great
> If I input  B= 48 I get  the permutations in numbers 01234 etc. which I also often use.
> Beyond 9 I can easily make items and replace the ascii chars with 10, 11 etc.
> 
> The DUPLICATES :
> I've been working on it to try to include this functionality into your script, but no dice yet. It is not really obvious at first sight.
> I'll continue to work on it though. If you or anyone has a bright idea, I'd love to hear it.

I don't know but it seems that the way to do this would be to work on permuting the character positions rather than the characters themselves. Perhaps using an array, charAtLoc[n], applying Geoff's algorithm to 1 though n, then replacing each number with charAtLoc[n] afterwards. I suspect it would be lots slower, though.

-- Peter

Peter M. Brigham
pmbrig at gmail.com
http://home.comcast.net/~pmbrig