Roger Hui wrote:
>
> The description pertains to the standard form of the
> cycle representation. <3 1 is not in standard form.
> A given cycle representation can be put into the
> standard form by two applications of C.
Well, my question is more like: "how do you get this:
C. <3 1
0 3 2 1
when you are not in the position of having standard cycle representation?
And my conjecture is this algorithm. Please advise:
- cycle_rep =: < 3 1
- r =: monadic_raze cycle_rep NB. 3 1
- perm_vector =: ( ( max r ) + 1 ) $ _1 NB. _1 _1 _1 _1
- any holes in the razed cycle_rep are "cycles of length 1" and can simply
fill in the value at the index as the value. In this case 0 goes to position
0 and 2 goes to position 2
- any remaining holes are filled in by unrolling the boxed cycles. In this
case, we just have 3 1, so we put 1 at index 3 and 3 and index 1
--
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