All, not just Raul and Jimmy,
I have chosen to reply to this earlier email because it contains
the "first attempt" solution I previously posted. That solution
ends inconclusively and created too many posts from me. However,
those posts and especially Raul's guidance have led to another
level of completeness. So "bear with ...":
The result from before is captured in the noun `test` which
contains 939 steps from my initial data which contained
16445 steps.
Recall that test was developed using the following expression.
test =: ((all :: ])&. ;:)^: _ blah blah data
The error was detected finally by removing the :: ] from
the attempted continuation, as shown next.
((all )&. ;:)^: _ test
|index error: ne0
| ((all)&.;:)^:_ test
The error in ne0 occurred because only NE,N, and S remain in the
nub of the iterative process, and nei, the feeder verb to neo,
feeds nei an index of 939, which is too big (by 1, of course).
Presently my correction is to repeat the iterative process on the
completed process with 3 changes shown next.
test =: ((all :: ])&. ;:)^: _ blah blah data
test2 =: ((all :: (1&|.)@])&. ;:)^: 939 test
The changes are detailed as follows.
0) :: ] is replaced by :: (1&|.)@]
1) _ is replaced by 939 which is #;:test
2) RHA of blah blah data is replaced by test
The good news is that the result is better but not completely
fool proof. The results show (below) that the reduced total
number of steps is 806, of which the 696 NE steps are all that
matter because the 110 N steps are redundant. You can visualize
that they are redundant by recognizing they are not cumulative;
rather think of them instead as alternatives, where they BOTH
begin at the initial position, sort of. (That's not a very
good explanation. Please help me.)
#;:test2
806
~.;:test2
┌──┬─┐
│NE│N│
└──┴─┘
#/.~ ;:test2
696 110
The bad news is first of all that the kind of phony interpretation
that I gave is required, and the results were only achieved by
dummying up the second iterative step to have a finite repetition
limit.
a) Can anyone think of a better way to avoid the requirement of a
second iterative step?
b) Can anyone give a better and more general explanation of how to
interpret and explain the final stage's result?
On Sat, Dec 16, 2017 at 2:32 PM, Brian Schott <[email protected]>
wrote:
> I have completed a first attempt at implementing Jimmy's
> ideas of parsing the symbolic list of directional moves.
> With Raul's help in making the tacit agenda code work, I
> put together the following J calculations. The main verb
> below is `all` and applying it iteratively to the data
> list, I put the result in the noun `test` for further
> analysis.
>
> As you can see test contains 939 directions, so further
> processing is required. Please see below for further
> comments.
>
>
> #;:test =: ((all :: ])&. ;:)^: _ toupper data rplc ',';' '
> 939 NB. if data includes an ending LF, use }: also
> ~.;: test
> ┌──┬─┬──┐
> │NE│N│SE│
> └──┴─┴──┘
> 15{.;: test NB. just to explore
> ┌──┬──┬──┬──┬──┬──┬──┬──┬──┬──┬──┬──┬──┬──┬──┐
> │NE│NE│NE│NE│NE│NE│NE│NE│NE│NE│NE│NE│NE│NE│NE│
> └──┴──┴──┴──┴──┴──┴──┴──┴──┴──┴──┴──┴──┴──┴──┘
> _15{.;: test NB. more exploring
> ┌──┬──┬─┬──┬──┬──┬──┬──┬──┬─┬─┬─┬─┬──┬─┐
> │NE│NE│N│SE│SE│NE│NE│SE│SE│N│N│N│N│NE│N│
> └──┴──┴─┴──┴──┴──┴──┴──┴──┴─┴─┴─┴─┴──┴─┘
> #/.~ ;:test
> 563 243 133 NB. NEs,Ns,SEs ; see nub next
> ~.;: test
> ┌──┬─┬──┐
> │NE│N│SE│
> └──┴─┴──┘
> +/563 133 110 NB. used because 243>133 => 133 more NEs
> 806
> +/\563 133 110 NB. looking again at cumulatives
> 563 696 806
>
> NB. BINGO, that 696 was the correct answer for my data
> NB. because 563+133 NEs "erase" the remaining 110 Ns
>
> So, this approach is enlightening, but I am not
> clear on how to generalize on the post-processing
> analysis, or how to change the processing to eliminate
> the need for the post-processing analysis.
>
> I'll attempt to supply the code needed below.
> The data may be different for each person on AoC, I'm not sure.
>
> swi =: [:(<./,]i.<./)(;:'NE SE N') i.~ ]
> sw0 =: a:-.~(a:"_)`(0,{.@[)`]}
> sw1 =: a:-.~(('S';a:)"_)`(0,{.@[)`]}
> sw2 =: a:-.~(('NW';a:)"_)`(0,{.@[)`]}
> swa =: ({.@] sw0 [)`({.@] sw1 [)`({.@] sw2 [)@.({:@] ) swi
>
> nwi =: [:(<./,]i.<./)(;:'SE NE S') i.~ ]
> nw0 =: a:-.~(a:"_)`(0,{.@[)`]}
> nw1 =: a:-.~(('N';a:)"_)`(0,{.@[)`]}
> nw2 =: a:-.~(('SW';a:)"_)`(0,{.@[)`]}
> nwa =: ({.@] nw0 [)`({.@] nw1 [)`({.@] nw2 [)@.({:@] ) nwi
>
> sei =: [:(<./,]i.<./)(;:'NW SW N') i.~ ]
> se0 =: a:-.~(a:"_)`(0,{.@[)`]}
> se1 =: a:-.~(('S';a:)"_)`(0,{.@[)`]}
> se2 =: a:-.~(('NE';a:)"_)`(0,{.@[)`]}
> sea =: ({.@] se0 [)`({.@] se1 [)`({.@] se2 [)@.({:@] ) sei
>
> nei =: [:(<./,]i.<./)(;:'SW NW S') i.~ ]
> ne0 =: a:-.~(a:"_)`(0,{.@[)`]}
> ne1 =: a:-.~(('N';a:)"_)`(0,{.@[)`]}
> ne2 =: a:-.~(('SE';a:)"_)`(0,{.@[)`]}
> nea =: ({.@] ne0 [)`({.@] ne1 [)`({.@] ne2 [)@.({:@] ) nei
>
> ni =: [:(<./,]i.<./)(;:'S SE SW') i.~ ]
> n0 =: a:-.~(a:"_)`(0,{.@[)`]}
> n1 =: a:-.~(('NE';a:)"_)`(0,{.@[)`]}
> n2 =: a:-.~(('NW';a:)"_)`(0,{.@[)`]}
> na =: ({.@] n0 [)`({.@] n1 [)`({.@] n2 [)@.({:@] ) ni
>
> si =: [:(<./,]i.<./)(;:'N SE SW') i.~ ]
> s0 =: a:-.~(a:"_)`(0,{.@[)`]}
> s1 =: a:-.~(('SE';a:)"_)`(0,{.@[)`]}
> s2 =: a:-.~(('SW';a:)"_)`(0,{.@[)`]}
> sa =: ({.@] s0 [)`({.@] s1 [)`({.@] s2 [)@.({:@] ) si
>
> all =: na`sa`nea`sea`nwa`swa@.(dirs@{.)
> dirs =: (;:'N S NE SE NW SW')&i.
>
>
> If you've gotten this far, you may be interested in an
> anomaly that turned up when further analyzing the results
> in `test`: i. could NOT locate the first <'N' in test,
> although i. successfully found the other 2 nub elements.
>
> #;:test2 =: ((all :: ])&. ;:)^: _ test
> 939
> (<'NE') i.~;: test
> 0
> (<'SE') i.~;: test
> 649
> (<'N') i.~;: test NB. this result should be < 939
> 939
>
--
(B=) <-----my sig
Brian Schott
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