permutations of a 6! numerically

[John Pierson]

Is it possible to change it from an array of say A B C D E F  to a word as in:- ABCDEF as a single element?

[altenbach]

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@John Pierson wrote:

Is it possible to change it from an array of say A B C D E F  to a word as in:- ABCDEF as a single element?

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Yes, my second example does that. 😄

[John Pierson]

extra kudos for you my man!

[Ray.R]

Very nice solution Christian.

🙂  Many kudos.

[Darin.K]

Could have been fun, too bad late lunch on West Coast means slow on the draw.  At any rate, the OP has a solution so I do not have to worry about minor details like saving for 8.2. The classic recursion solution is elegant (like most recursive solutions), but native recursion (in LV9+) is slow, and VI server recursion is downright glacial.  I think the physicist side of DFGray showed up, rolling the dice is a simple-yet-effective treatment in these cases, I would probably have been putting Riffle to good use here.

Altenbach's solution is (needless-to-say) masterfully efficient, I only have a few quibbles.  It assumes the elements are distinct, but oftentimes, especially with letters, elements can be repeated.  Second, while there is considerable in-placeness, it is often not the best idea to be carrying around all possible combinations since that can become quite a large number in a hurry.

So, given this good excuse to dust off Knuth's book, and as an added bonus implement a 700 year old algorithm, here is my take.  Shamelessly LV9.0 (or at least 8.6 for the IPE and conditional For Loops).  This routine is seriously in-place, each time it is run it generates the next permutation given the previous one.  Using for example the letters 'aab' it returns only three permutations instead of six.

[Darin.K]

Oops.  seemed to attach same file twice last time.  Here is the VI which uses a while loop to find all permutations.  Better hurry before altenbach notices...

[altenbach]

What's the difference between the two attachments?

EDIT: Nevermind, just saw your new post... 😉

[Darin.K]

Post collision earlier.

[altenbach]

Looks good. Do you have a link to the algorithm?

(One minor flaw: an empty string input should probably give an empty array as output.)

[altenbach]

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altenbach wrote:

(One minor flaw: an empty string input should probably give an empty array as output.)

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Quick fix:

In the TRUE case, check for "empty string?" and wire the output to the tunnel, replacing the boolean diagram constant.