to see why, try this
B="1 f A
On Dec 15, 2015 7:57 PM, "Linda Alvord" <[email protected]> wrote:
> Why isn't the result 0 0 0 0 0 1 0 0 ?
>
> A=:'^<v>'
> B=:'<V>^'
> f=: 13 :'((|.|:|.4|+/~i.4),4|+/~i.4){y'
> f A
> v<^>
> <^>v
> ^>v<
> >v<^
> ^<v>
> <v>^
> v>^<
> >^<v
> B-:"1 f A
> 0 0 0 0 0 0 0 0
>
> Linda
>
> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]] On Behalf Of David
> Lambert
> Sent: Thursday, December 3, 2015 9:40 AM
> To: programming <[email protected]>
> Subject: [Jprogramming] adventofcode day 3
>
> Say P is a rank 2 list of 2D coordinates
> 4{.P
> 0 0
> 0 1
> 0 2
> _1 2
>
> Let's map the flight.
>
> NB. shift moves origin making minimum coordinates independently 0 NB. use:
> shift COORDINATES
> shift=: -"1 <./
>
> NB. grid generates an array of zeros large enough for only the positive
> coords NB. use: grid COORDS
> grid=: 0 $~ >:@:(>./)
>
> NB. COORDS draw GRID NB. color by number
> draw=: (i.@#@[)`(;/@:[)`]}
>
> load'viewmat'
> flight =: viewmat @: (draw grid) @: shift
>
> flight P
>
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