Newer
Older
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
let count_neighbours [n] (board: [n][n]i8) : [n][n]i8 =
let north = rotate (-1) board
let south = rotate 1 board
let east = map(rotate 1) board
let west = map(rotate (-1)) board
let north_east = map(rotate 1) north
let north_west = map(rotate (-1)) north
let south_east = map(rotate 1) south
let south_west = map(rotate (-1)) south
in map3 (\(nwr,nr,ner) (wr, br, er) (swr, sr, ser) ->
map3 (\(nw,n,ne) (w, _, e) (sw, s, se) -> nw + n + ne + w + e + sw + s + se)
(zip3 nwr nr ner) (zip3 wr br er) (zip3 swr sr ser))
(zip3 north_west north north_east) (zip3 west board east) (zip3 south_west south south_east)
let augment_board [n][m] (chunk_board :[n][n]i8) (envelope_board: [4][m]i8): [m][m]i8 =
tabulate_2d (m) (m) (\i j ->
-- North
if (i == 0) then envelope_board[0,j]
-- East
else if (j == m-1) then envelope_board[1,i]
-- South
else if (i == m-1) then envelope_board[2,j]
-- West
else if (j == 0) then envelope_board[3,i]
else chunk_board[i-1,j-1])
entry next_chunk_board [n][m] (chunk_board :[n][n]i8) (envelope_board: [4][m]i8) :[n][n]i8 =
let augmented_board = augment_board chunk_board envelope_board
let neighbours = count_neighbours augmented_board
let next_board = map2 (\augmented_board_r neighbours_r ->
map2(\cell nb_alive_cells ->
if (cell == 1 && (nb_alive_cells == 2 || nb_alive_cells == 3)) || (cell == 0 && nb_alive_cells == 3)
then 1
else 0)
augmented_board_r neighbours_r)
augmented_board neighbours
in next_board[1:n+1, 1:n+1] :> [n][n]i8
entry get_envelope [n] (chunk_board: [n][n]i8): [4][n]i8 =
let north = chunk_board[0]
let south = chunk_board[n-1]
let tr_chunk_board = transpose chunk_board
let east = tr_chunk_board[n-1]
let west = tr_chunk_board[0]
in [north, east, south, west]