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{{draft task}}
Section 3.3 of [[https://pdfs.semanticscholar.org/4a7c/d245f6f6a4ef933c6cf697832607f71a39c1.pdf Generalised 2-designs with Block Size 3(Andy L. Drizen)]] describes a method of generating Latin Squares of order n attributed to Jacobson and Matthews. The purpose of this task is to produce a function which given a valid Latin Square transforms it to another using this method.
;part 1 Use one of the 4 [[Latin Squares in reduced form]] of order 4 as X0 to generate 10000 Latin Squares using X(n-1) to generate X(n). Convert the resulting Latin Squares to their reduced form, display them and the number of times each is produced.
;part 2 As above for order 5, but do not display the squares. Generate the 56 [[Latin Squares in reduced form]] of order 5, confirm that all 56 are produced by the Jacobson and Matthews technique and display the number of each produced.
;part 3 Generate 750 Latin Squares of order 42 and display the 750th.
;part 4 Generate 1000 Latin Squares of order 256. Don't display anything but confirm the approximate time taken and anything else you may find interesting
=={{header|F_Sharp|F#}}==
The Functions
// Jacobson and Matthews technique for generating Latin Squares. Nigel Galloway: August 5th., 2019 let R=let N=System.Random() in (fun n->N.Next(n)) let jmLS α X0= let X0=Array2D.copy X0 let N=let N=[|[0..α-1];[α-1..(-1)..0]|] in (fun()->N.[R 2]) let rec randLS i j z n g s= X0.[i,g]<-s; X0.[n,j]<-s if X0.[n,g]=s then X0.[n,g]<-z; X0 else randLS n g s (List.find(fun n->X0.[n,g]=s)(N())) (List.find(fun g->X0.[n,g]=s)(N())) (if (R 2)=0 then let t=X0.[n,g] in X0.[n,g]<-z; t else z) let i,j=R α,R α let z =let z=1+(R (α-1)) in if z<X0.[i,j] then z else 1+(z+1)%α let n,g,s=let N=[0..α-1] in (List.find(fun n->X0.[n,j]=z) N,List.find(fun n->X0.[i,n]=z) N,X0.[i,j]) X0.[i,j]<-z; randLS i j z n g s let asNormLS α= let n=Array.init (Array2D.length1 α) (fun n->(α.[n,0]-1,n))|>Map.ofArray let g=Array.init (Array2D.length1 α) (fun g->(α.[n.[0],g]-1,g))|>Map.ofArray Array2D.init (Array2D.length1 α) (Array2D.length1 α) (fun i j->α.[n.[i],g.[j]]) let randLS α=Seq.unfold(fun g->Some(g,jmLS α g))(Array2D.init α α (fun n g->1+(n+g)%α))
The Task
;part 1
randLS 4 |> Seq.take 10000 |> Seq.map asNormLS |> Seq.countBy id |> Seq.iter(fun n->printf "%A was produced %d times\n\n" (fst n)(snd n))
{{out}}
[[1; 2; 3; 4]
[2; 3; 4; 1]
[3; 4; 1; 2]
[4; 1; 2; 3]] was produced 2920 times
[[1; 2; 3; 4]
[2; 4; 1; 3]
[3; 1; 4; 2]
[4; 3; 2; 1]] was produced 2262 times
[[1; 2; 3; 4]
[2; 1; 4; 3]
[3; 4; 2; 1]
[4; 3; 1; 2]] was produced 2236 times
[[1; 2; 3; 4]
[2; 1; 4; 3]
[3; 4; 1; 2]
[4; 3; 2; 1]] was produced 2582 times
;part 2
randLS 5 |> Seq.take 10000 |> Seq.map asNormLS |> Seq.countBy id |> Seq.iteri(fun n g->printf "%d(%d) " (n+1) (snd g)); printfn ""
{{out}}
1(176) 2(171) 3(174) 4(165) 5(168) 6(182) 7(138) 8(205) 9(165) 10(174) 11(157) 12(187) 13(181) 14(211) 15(184) 16(190) 17(190) 18(192) 19(146) 20(200) 21(162) 22(153) 23(193) 24(156) 25(148) 26(188) 27(186) 28(198) 29(178) 30(217) 31(185) 32(172) 33(223) 34(147) 35(203) 36(167) 37(188) 38(152) 39(165) 40(187) 41(160) 42(199) 43(140) 44(202) 45(186) 46(182) 47(175) 48(161) 49(179) 50(175) 51(201) 52(195) 53(205) 54(183) 55(155) 56(178)
;part 3
let q=Seq.item 749 (randLS 42) for n in [0..41] do (for g in [0..41] do printf "%3d" q.[n,g]); printfn ""
{{out}}
16 7 41 15 17 40 12 9 10 5 19 29 21 18 8 22 3 36 23 31 11 38 13 30 2 33 6 42 39 14 32 20 28 35 26 1 34 37 27 24 4 25
38 25 36 32 40 29 35 27 8 26 31 15 9 7 16 11 4 3 12 20 23 33 5 24 41 14 30 34 42 17 39 18 37 22 21 13 1 10 6 19 2 28
8 34 27 25 21 31 1 23 37 36 26 13 22 24 35 17 10 40 41 30 42 7 15 2 18 3 29 11 32 4 38 39 9 5 16 14 28 12 20 33 19 6
33 35 13 34 15 24 4 29 41 27 3 17 10 26 39 23 30 32 1 38 16 25 37 14 6 28 19 9 40 5 18 7 42 11 31 20 12 22 2 21 8 36
2 42 20 1 7 26 11 10 39 41 34 22 40 23 24 29 14 17 5 33 38 30 6 13 3 16 18 19 31 15 28 21 36 37 32 27 8 4 25 9 35 12
25 33 14 40 28 30 31 24 29 4 8 20 26 38 12 35 2 39 16 6 13 21 18 17 5 41 23 3 36 7 34 22 27 1 10 42 11 19 15 32 37 9
17 22 35 28 30 18 21 2 15 39 5 40 27 13 1 34 38 37 26 23 41 36 4 3 11 6 20 8 9 10 12 24 31 25 7 29 16 32 42 14 33 19
14 9 19 7 26 15 10 4 36 25 22 23 39 16 2 40 18 1 38 13 21 37 34 31 35 24 12 27 11 3 5 6 17 20 41 33 32 29 8 30 28 42
5 27 24 13 2 36 25 30 23 9 6 14 35 15 42 39 16 26 21 34 33 31 3 1 29 12 38 17 37 19 40 4 7 8 22 41 20 28 32 10 18 11
19 41 28 26 8 10 30 35 18 33 15 27 25 21 29 42 23 12 17 2 5 1 38 6 20 7 34 4 13 36 24 31 14 3 11 32 39 40 9 22 16 37
41 10 3 19 22 9 27 40 1 29 16 42 33 39 34 7 37 20 11 12 4 18 35 8 28 26 36 5 17 30 25 32 6 15 24 21 13 23 14 2 38 31
42 3 16 36 33 21 20 14 31 22 9 38 29 19 37 13 28 10 35 18 39 26 25 27 4 30 15 23 41 24 11 1 40 7 5 17 6 2 12 8 34 32
23 31 34 41 38 33 3 28 4 1 30 25 6 2 20 14 13 24 8 42 7 12 39 32 22 29 5 37 15 9 27 10 35 36 19 40 17 18 16 11 26 21
37 16 30 11 4 32 42 33 13 6 14 2 15 27 18 31 20 41 39 40 9 24 36 5 10 8 1 26 3 34 22 28 38 19 29 23 21 25 35 12 17 7
1 19 26 22 16 25 36 39 3 23 41 37 34 6 17 32 40 21 10 27 12 9 31 7 13 4 24 29 8 11 2 5 15 18 35 28 30 20 33 38 42 14
11 13 23 30 25 41 6 31 14 32 27 36 19 17 10 33 21 15 7 5 8 28 16 35 34 42 40 2 38 39 9 26 20 24 37 4 18 3 22 1 12 29
24 17 29 38 23 39 32 5 11 15 35 12 8 10 40 1 22 25 2 36 28 4 42 21 9 20 3 31 16 41 13 30 19 34 33 18 27 6 7 37 14 26
36 4 6 24 12 20 2 34 40 11 32 9 28 8 38 21 5 31 42 17 14 29 19 22 25 15 7 18 30 26 1 13 16 41 23 39 37 33 3 35 10 27
20 39 2 12 32 7 22 3 17 10 37 6 18 40 27 5 42 35 28 4 24 14 33 29 30 31 26 13 19 23 36 41 1 21 9 11 15 8 34 16 25 38
35 18 37 6 5 13 29 8 24 19 38 34 12 31 21 10 33 7 3 41 15 42 20 11 27 40 16 14 23 1 4 2 22 32 28 9 25 30 26 39 36 17
10 32 9 33 39 19 41 38 35 18 28 26 14 30 7 4 1 22 37 21 31 40 27 15 42 34 2 25 5 12 23 36 8 6 17 3 29 24 11 13 20 16
13 28 39 2 31 8 9 37 21 16 40 19 42 36 41 3 12 14 20 10 17 34 1 33 32 35 25 30 18 38 15 11 24 23 6 26 4 5 29 7 27 22
7 40 12 39 18 3 16 21 42 17 1 32 5 33 13 6 41 8 29 14 34 35 24 36 38 25 31 28 26 27 20 37 23 2 30 10 22 9 19 4 11 15
4 21 7 17 35 34 19 25 12 42 11 1 30 28 36 26 32 23 14 29 2 20 8 41 24 27 22 15 10 18 37 9 39 38 13 6 3 16 31 40 5 33
34 23 42 14 41 27 37 6 9 31 4 5 7 1 25 16 35 30 33 11 19 3 26 12 17 38 8 20 24 13 29 15 32 28 40 22 2 39 18 36 21 10
30 6 21 9 20 17 5 32 38 13 12 28 16 35 22 36 34 29 40 39 25 15 14 37 33 11 4 41 1 2 19 3 26 27 42 8 10 7 23 31 24 18
6 38 8 10 42 35 13 1 16 37 21 3 11 34 32 20 29 18 25 22 36 5 30 26 39 23 28 12 2 31 7 19 33 40 14 24 9 41 17 27 15 4
29 15 1 21 14 11 26 17 30 38 10 33 36 20 4 18 39 16 31 3 35 2 32 28 19 13 42 7 12 8 6 40 5 9 25 37 24 27 41 23 22 34
21 36 32 8 6 23 15 19 2 14 18 4 3 11 5 28 26 13 34 25 30 17 7 42 16 22 39 40 29 37 33 12 41 10 27 31 35 38 24 20 9 1
39 20 31 29 19 4 38 16 27 30 24 11 2 3 33 15 8 28 18 37 10 13 9 23 36 1 17 22 25 32 26 35 12 42 34 7 40 14 21 5 6 41
12 11 17 42 9 2 14 7 22 24 25 31 38 41 15 19 36 33 32 28 1 10 29 40 23 18 37 39 6 21 35 27 3 16 8 30 5 26 4 34 13 20
18 29 33 16 27 42 40 26 7 8 39 24 41 5 30 38 6 9 13 1 32 22 2 34 12 37 11 10 35 20 14 17 21 4 15 19 23 36 28 25 31 3
28 2 4 18 11 5 23 20 25 35 42 30 31 14 3 9 24 27 19 7 22 6 12 10 1 32 41 36 21 33 16 34 29 13 39 15 38 17 37 26 40 8
3 26 11 35 24 37 17 36 6 7 13 41 4 32 9 2 31 34 22 15 29 8 40 18 21 5 27 1 14 16 10 38 25 33 20 12 19 42 39 28 30 23
31 5 22 27 10 6 8 13 34 2 33 7 32 42 26 12 19 4 15 9 40 16 28 38 37 39 35 24 20 29 17 23 11 14 3 25 41 21 36 18 1 30
15 24 5 37 3 28 7 22 19 34 20 18 17 12 23 8 25 11 36 16 27 41 10 4 31 2 9 32 33 42 21 14 13 29 38 35 26 1 30 6 39 40
27 37 25 5 13 16 24 41 28 3 2 10 23 4 14 30 11 38 6 19 26 32 21 20 40 9 33 35 34 22 42 8 18 17 12 36 31 15 1 29 7 39
26 30 10 3 36 22 33 11 5 20 29 21 13 25 31 37 17 2 9 35 18 27 23 39 14 19 32 16 28 6 8 42 4 12 1 38 7 34 40 15 41 24
32 8 18 31 1 14 34 12 33 28 17 39 37 9 19 27 7 5 30 24 20 23 11 25 15 36 21 6 22 40 41 16 10 26 4 2 42 35 38 3 29 13
9 14 40 23 37 38 18 15 20 12 36 8 1 22 28 24 27 42 4 32 6 11 41 19 26 10 13 21 7 25 30 29 34 39 2 16 33 31 5 17 3 35
22 12 15 4 34 1 39 42 32 40 7 35 20 29 11 25 9 6 24 26 37 19 17 16 8 21 14 38 27 28 3 33 30 31 18 5 36 13 10 41 23 2
40 1 38 20 29 12 28 18 26 21 23 16 24 37 6 41 15 19 27 8 3 39 22 9 7 17 10 33 4 35 31 25 2 30 36 34 14 11 13 42 32 5
;part 4 Generating 1000 Latin Squares of order 256 takes about 1.5secs
printfn "%d" (Array2D.length1 (Seq.item 999 (randLS 256)))
{{out}}
256
Real: 00:00:01.512, CPU: 00:00:01.970, GC gen0: 10, gen1: 10
Go
The J & M implementation is based on the C code [https://brainwagon.org/2016/05/17/code-for-generating-a-random-latin-square/ here] which has been heavily optimized following advice and clarification by Nigel Galloway (see Talk page) on the requirements of this task.
Part 4 is taking about 6.5 seconds on my Celeron @1.6 GHz but will be much faster on a more modern machine. Being able to compute random, uniformly distributed, Latin squares of order 256 reasonably quickly is interesting from a secure communications or cryptographic standpoint as the symbols of such a square can represent the 256 characters of the various extended ASCII encodings.
package main import ( "fmt" "math/rand" "time" ) type ( vector []int matrix []vector cube []matrix ) func toReduced(m matrix) matrix { n := len(m) r := make(matrix, n) for i := 0; i < n; i++ { r[i] = make(vector, n) copy(r[i], m[i]) } for j := 0; j < n-1; j++ { if r[0][j] != j { for k := j + 1; k < n; k++ { if r[0][k] == j { for i := 0; i < n; i++ { r[i][j], r[i][k] = r[i][k], r[i][j] } break } } } } for i := 1; i < n-1; i++ { if r[i][0] != i { for k := i + 1; k < n; k++ { if r[k][0] == i { for j := 0; j < n; j++ { r[i][j], r[k][j] = r[k][j], r[i][j] } break } } } } return r } // 'm' is assumed to be 0 based func printMatrix(m matrix) { n := len(m) for i := 0; i < n; i++ { for j := 0; j < n; j++ { fmt.Printf("%2d ", m[i][j]+1) // back to 1 based } fmt.Println() } fmt.Println() } // converts 4 x 4 matrix to 'flat' array func asArray16(m matrix) [16]int { var a [16]int k := 0 for i := 0; i < 4; i++ { for j := 0; j < 4; j++ { a[k] = m[i][j] k++ } } return a } // converts 5 x 5 matrix to 'flat' array func asArray25(m matrix) [25]int { var a [25]int k := 0 for i := 0; i < 5; i++ { for j := 0; j < 5; j++ { a[k] = m[i][j] k++ } } return a } // 'a' is assumed to be 0 based func printArray16(a [16]int) { for i := 0; i < 4; i++ { for j := 0; j < 4; j++ { k := i*4 + j fmt.Printf("%2d ", a[k]+1) // back to 1 based } fmt.Println() } fmt.Println() } func shuffleCube(c cube) { n := len(c[0]) proper := true var rx, ry, rz int for { rx = rand.Intn(n) ry = rand.Intn(n) rz = rand.Intn(n) if c[rx][ry][rz] == 0 { break } } for { var ox, oy, oz int for ; ox < n; ox++ { if c[ox][ry][rz] == 1 { break } } if !proper && rand.Intn(2) == 0 { for ox++; ox < n; ox++ { if c[ox][ry][rz] == 1 { break } } } for ; oy < n; oy++ { if c[rx][oy][rz] == 1 { break } } if !proper && rand.Intn(2) == 0 { for oy++; oy < n; oy++ { if c[rx][oy][rz] == 1 { break } } } for ; oz < n; oz++ { if c[rx][ry][oz] == 1 { break } } if !proper && rand.Intn(2) == 0 { for oz++; oz < n; oz++ { if c[rx][ry][oz] == 1 { break } } } c[rx][ry][rz]++ c[rx][oy][oz]++ c[ox][ry][oz]++ c[ox][oy][rz]++ c[rx][ry][oz]-- c[rx][oy][rz]-- c[ox][ry][rz]-- c[ox][oy][oz]-- if c[ox][oy][oz] < 0 { rx, ry, rz = ox, oy, oz proper = false } else { proper = true break } } } func toMatrix(c cube) matrix { n := len(c[0]) m := make(matrix, n) for i := 0; i < n; i++ { m[i] = make(vector, n) } for i := 0; i < n; i++ { for j := 0; j < n; j++ { for k := 0; k < n; k++ { if c[i][j][k] != 0 { m[i][j] = k break } } } } return m } // 'from' matrix is assumed to be 1 based func makeCube(from matrix, n int) cube { c := make(cube, n) for i := 0; i < n; i++ { c[i] = make(matrix, n) for j := 0; j < n; j++ { c[i][j] = make(vector, n) var k int if from == nil { k = (i + j) % n } else { k = from[i][j] - 1 } c[i][j][k] = 1 } } return c } func main() { rand.Seed(time.Now().UnixNano()) // part 1 fmt.Println("PART 1: 10,000 latin Squares of order 4 in reduced form:\n") from := matrix{{1, 2, 3, 4}, {2, 1, 4, 3}, {3, 4, 1, 2}, {4, 3, 2, 1}} freqs4 := make(map[[16]int]int, 10000) c := makeCube(from, 4) for i := 1; i <= 10000; i++ { shuffleCube(c) m := toMatrix(c) rm := toReduced(m) a16 := asArray16(rm) freqs4[a16]++ } for a, freq := range freqs4 { printArray16(a) fmt.Printf("Occurs %d times\n\n", freq) } // part 2 fmt.Println("\nPART 2: 10,000 latin squares of order 5 in reduced form:") from = matrix{{1, 2, 3, 4, 5}, {2, 3, 4, 5, 1}, {3, 4, 5, 1, 2}, {4, 5, 1, 2, 3}, {5, 1, 2, 3, 4}} freqs5 := make(map[[25]int]int, 10000) c = makeCube(from, 5) for i := 1; i <= 10000; i++ { shuffleCube(c) m := toMatrix(c) rm := toReduced(m) a25 := asArray25(rm) freqs5[a25]++ } count := 0 for _, freq := range freqs5 { count++ if count > 1 { fmt.Print(", ") } if (count-1)%8 == 0 { fmt.Println() } fmt.Printf("%2d(%3d)", count, freq) } fmt.Println("\n") // part 3 fmt.Println("\nPART 3: 750 latin squares of order 42, showing the last one:\n") var m42 matrix c = makeCube(nil, 42) for i := 1; i <= 750; i++ { shuffleCube(c) if i == 750 { m42 = toMatrix(c) } } printMatrix(m42) // part 4 fmt.Println("\nPART 4: 1000 latin squares of order 256:\n") start := time.Now() c = makeCube(nil, 256) for i := 1; i <= 1000; i++ { shuffleCube(c) } elapsed := time.Since(start) fmt.Printf("Generated in %s\n", elapsed) }
{{out}} Sample run:
PART 1: 10,000 latin Squares of order 4 in reduced form:
1 2 3 4
2 1 4 3
3 4 2 1
4 3 1 2
Occurs 2550 times
1 2 3 4
2 4 1 3
3 1 4 2
4 3 2 1
Occurs 2430 times
1 2 3 4
2 1 4 3
3 4 1 2
4 3 2 1
Occurs 2494 times
1 2 3 4
2 3 4 1
3 4 1 2
4 1 2 3
Occurs 2526 times
PART 2: 10,000 latin squares of order 5 in reduced form:
1(165), 2(173), 3(167), 4(204), 5(173), 6(165), 7(215), 8(218),
9(168), 10(157), 11(205), 12(152), 13(187), 14(173), 15(215), 16(185),
17(179), 18(176), 19(179), 20(160), 21(150), 22(166), 23(191), 24(181),
25(179), 26(192), 27(187), 28(186), 29(176), 30(196), 31(141), 32(187),
33(165), 34(189), 35(147), 36(175), 37(172), 38(162), 39(180), 40(172),
41(189), 42(159), 43(197), 44(158), 45(178), 46(179), 47(193), 48(175),
49(207), 50(174), 51(181), 52(179), 53(193), 54(171), 55(153), 56(204)
PART 3: 750 latin squares of order 42, showing the last one:
29 2 17 41 34 30 8 33 39 7 20 27 12 6 31 14 40 35 25 9 10 32 19 16 24 42 3 26 5 23 1 28 4 13 38 18 21 37 22 15 36 11
17 15 11 31 9 38 26 10 1 28 37 8 34 41 21 22 12 5 35 36 13 20 29 42 18 3 19 24 39 32 27 23 16 25 33 4 40 6 2 30 7 14
36 42 35 39 15 34 37 18 32 25 22 31 4 17 3 19 13 11 8 23 12 24 28 27 16 1 6 9 29 40 7 5 2 14 30 26 41 10 21 33 38 20
21 13 16 42 3 32 2 26 27 17 15 11 25 37 29 6 19 10 12 7 31 18 36 9 39 41 30 40 35 33 22 1 28 38 24 8 34 23 4 20 14 5
22 39 13 7 38 9 34 41 37 36 35 6 21 26 17 16 4 30 40 20 8 15 25 19 32 2 11 28 23 24 31 10 42 3 27 12 33 14 1 29 5 18
33 36 34 3 13 4 7 14 2 29 6 12 31 23 26 17 8 20 32 21 19 41 37 5 38 30 25 11 24 35 42 27 18 16 39 15 10 22 28 1 9 40
14 31 7 22 39 23 32 34 16 33 24 4 40 42 12 25 35 26 18 28 11 3 15 21 20 9 13 19 1 10 2 41 29 6 17 30 5 38 37 8 27 36
9 3 6 30 19 39 14 16 4 15 29 28 23 24 32 10 18 41 37 38 40 34 8 25 2 22 31 5 17 26 36 33 13 21 12 35 7 20 11 27 42 1
2 18 28 5 6 7 40 35 3 20 8 34 42 39 37 33 26 23 22 13 14 4 12 15 17 25 36 31 16 29 38 19 32 41 1 27 24 11 30 9 10 21
27 34 19 15 33 22 5 36 9 30 14 1 24 8 38 42 41 39 7 40 4 37 11 23 29 26 18 12 3 21 35 16 20 10 31 25 17 28 6 32 2 13
41 16 1 35 22 13 20 29 6 38 5 24 19 10 25 27 17 18 11 32 9 7 2 36 4 34 40 21 33 12 8 30 15 42 37 23 14 26 3 39 31 28
7 1 15 16 27 31 18 24 20 8 36 38 10 34 9 4 42 29 2 3 26 39 5 22 41 21 37 30 14 11 33 35 25 23 40 28 13 19 17 6 32 12
1 10 20 32 23 5 30 12 8 9 21 36 15 14 18 37 33 31 26 39 41 16 6 24 22 35 29 42 27 28 3 38 11 2 7 34 4 40 19 17 13 25
6 32 42 11 20 40 27 25 41 22 17 16 26 29 15 7 23 36 39 34 28 13 18 3 10 37 8 14 2 31 4 24 5 19 9 21 38 1 33 12 30 35
35 40 30 19 21 12 17 4 22 27 3 20 11 9 8 23 24 42 14 10 39 28 26 29 33 13 41 16 34 25 32 37 7 18 5 6 15 2 36 38 1 31
15 26 40 1 28 20 9 21 7 5 13 18 30 22 10 8 3 25 6 2 17 36 38 31 14 19 35 23 12 27 11 39 24 4 41 32 29 34 42 16 37 33
3 6 26 12 32 1 13 8 42 37 25 7 9 16 35 5 29 21 24 27 34 17 14 2 15 11 28 33 20 38 18 22 39 40 23 10 31 30 41 36 19 4
31 38 36 21 16 26 28 30 15 3 32 41 18 1 6 29 9 17 5 35 7 40 27 37 13 20 23 22 11 19 12 42 34 8 10 14 25 39 24 4 33 2
40 4 22 38 35 11 21 17 31 1 28 19 37 2 42 24 14 12 13 30 33 25 34 32 27 36 39 3 9 15 10 18 8 5 6 41 26 16 29 7 20 23
5 17 39 4 26 14 31 37 35 11 38 3 1 30 19 36 20 33 15 16 21 29 9 6 25 27 2 13 41 34 24 12 10 32 22 7 28 18 40 42 23 8
8 29 24 26 31 21 39 23 11 14 19 10 20 15 7 35 32 38 1 12 25 22 16 4 6 40 42 41 18 30 28 2 17 36 3 13 37 33 27 5 34 9
11 25 14 17 18 24 19 32 33 31 7 26 2 21 20 30 15 27 23 41 29 35 39 28 34 12 10 4 8 42 5 13 37 9 16 40 1 36 38 3 6 22
26 21 18 25 29 15 1 13 19 2 34 23 38 27 41 3 10 22 17 4 16 11 42 12 8 6 5 35 30 39 37 14 9 24 36 33 20 7 31 28 40 32
25 27 12 33 17 35 24 9 28 10 42 21 8 13 2 15 34 16 3 18 5 31 41 7 23 4 1 6 22 14 19 36 40 37 26 38 30 32 20 11 39 29
23 19 25 9 30 37 38 40 14 41 31 17 7 4 16 11 1 6 33 5 24 2 3 8 21 29 34 32 28 22 15 20 12 35 18 36 39 27 10 13 26 42
34 9 10 13 2 6 22 31 26 40 1 14 41 3 11 12 37 32 27 29 35 19 30 33 28 38 21 25 7 5 16 8 36 15 20 42 23 17 39 18 4 24
20 11 37 28 41 8 10 15 36 12 26 33 39 32 13 1 25 9 42 19 3 6 24 14 5 23 7 27 38 2 30 4 22 34 35 31 18 29 16 40 21 17
28 30 21 23 24 29 3 1 10 6 33 2 27 40 14 34 31 15 19 37 18 9 4 13 35 8 12 20 36 16 17 32 41 7 25 39 42 5 26 22 11 38
32 12 8 40 11 16 23 28 18 42 41 30 3 38 33 2 22 19 4 25 37 1 31 20 36 5 9 7 13 17 14 6 27 39 34 24 35 21 15 26 29 10
18 37 41 10 36 28 11 42 13 34 2 35 5 7 22 40 39 3 30 1 38 27 20 17 19 33 26 15 25 6 21 29 23 31 4 9 32 8 12 14 24 16
39 24 29 37 25 19 33 27 17 16 10 40 36 12 30 41 11 4 34 15 2 5 32 1 31 14 38 18 42 3 9 7 6 20 21 22 8 13 23 35 28 26
19 14 5 8 40 3 29 6 21 26 23 15 16 33 28 31 38 13 9 17 27 12 10 11 7 24 20 1 4 41 39 25 30 22 32 2 36 42 35 34 18 37
37 7 32 34 8 36 41 2 12 24 16 39 33 31 4 13 6 28 38 22 20 42 40 18 9 10 14 29 26 1 23 15 21 27 19 17 11 3 5 25 35 30
4 41 27 2 42 17 15 38 30 35 12 25 13 28 39 20 5 1 16 33 36 23 7 40 37 32 24 10 31 8 6 21 14 26 29 11 3 9 18 19 22 34
38 35 23 36 4 10 12 11 5 21 27 32 17 25 24 18 28 40 20 6 42 14 22 30 26 39 33 8 37 7 13 34 1 29 15 19 2 41 9 31 16 3
30 33 31 24 12 41 36 19 23 32 4 37 29 11 34 39 16 14 21 42 6 26 1 38 3 17 22 2 40 18 20 9 35 28 13 5 27 15 25 10 8 7
42 28 3 14 1 25 16 22 34 23 39 9 35 5 40 26 36 7 10 31 32 21 13 41 30 18 4 38 6 37 29 17 33 12 11 20 19 24 8 2 15 27
16 5 38 6 10 27 4 3 40 18 11 13 22 35 1 21 2 34 36 8 23 30 17 39 42 7 15 37 32 20 26 31 19 33 28 29 9 25 14 24 12 41
24 23 33 18 14 2 25 39 29 19 9 5 28 20 27 38 7 8 31 11 15 10 35 34 12 16 32 17 21 36 40 3 26 30 42 1 22 4 13 37 41 6
12 20 2 29 5 33 42 7 24 4 18 22 14 19 36 9 27 37 28 26 30 38 23 10 11 31 17 34 15 13 41 40 3 1 8 16 6 35 32 21 25 39
13 8 9 27 37 42 6 20 25 39 40 29 32 18 5 28 30 24 41 14 22 33 21 35 1 15 16 36 10 4 34 26 38 11 2 3 12 31 7 23 17 19
10 22 4 20 7 18 35 5 38 13 30 42 6 36 23 32 21 2 29 24 1 8 33 26 40 28 27 39 19 9 25 11 31 17 14 37 16 12 34 41 3 15
PART 4: 1000 latin squares of order 256:
Generated in 6.581088256s
Phix
{{trans|Go}}
function shuffleCube(sequence c)
integer n = length(c), rx, ry, rz
bool proper = true
while true do
rx = rand(n)
ry = rand(n)
rz = rand(n)
if c[rx][ry][rz] == 0 then exit end if
end while
while true do
integer ox, oy, oz
for ox=1 to n do
if c[ox][ry][rz] == 1 then exit end if
end for
if not proper and rand(2)==2 then
for ox=ox+1 to n do
if c[ox][ry][rz] == 1 then exit end if
end for
end if
for oy=1 to n do
if c[rx][oy][rz] == 1 then exit end if
end for
if not proper and rand(2)==2 then
for oy=oy+1 to n do
if c[rx][oy][rz] == 1 then exit end if
end for
end if
for oz=1 to n do
if c[rx][ry][oz] == 1 then exit end if
end for
if not proper and rand(2)==2 then
for oz=oz+1 to n do
if c[rx][ry][oz] == 1 then exit end if
end for
end if
c[rx][ry][rz] += 1
c[rx][oy][oz] += 1
c[ox][ry][oz] += 1
c[ox][oy][rz] += 1
c[rx][ry][oz] -= 1
c[rx][oy][rz] -= 1
c[ox][ry][rz] -= 1
c[ox][oy][oz] -= 1
if c[ox][oy][oz] < 0 then
{rx, ry, rz} = {ox, oy, oz}
proper = false
else
proper = true
exit
end if
end while
return c
end function
function toMatrix(sequence c)
integer n = length(c)
sequence m = repeat(repeat(0,n),n)
for i=1 to n do
for j=1 to n do
for k=1 to n do
if c[i][j][k] != 0 then
m[i][j] = k
exit
end if
end for
end for
end for
return m
end function
function toReduced(sequence m)
integer n := length(m)
for j=1 to n-1 do
if m[1][j]!=j then
for k=j+1 to n do
if m[1][k]==j then
for i=1 to n do
{m[i][j], m[i][k]} = {m[i][k], m[i][j]}
end for
exit
end if
end for
end if
end for
for i=2 to n-1 do
if m[i][1]!=i then
for k=i+1 to n do
if m[k][1]==i then
for j=1 to n do
{m[i][j], m[k][j]} = {m[k][j], m[i][j]}
end for
exit
end if
end for
end if
end for
return m
end function
function makeCube(object from, integer n)
sequence c = repeat(repeat(repeat(0,n),n),n)
for i=1 to n do
for j=1 to n do
integer k = iff(from==NULL?mod(i+j,n)+1:from[i][j])
c[i][j][k] = 1
end for
end for
return c
end function
procedure main()
printf(1,"Part 1: 10,000 latin Squares of order 4 in reduced form:\n\n")
sequence from = {{1, 2, 3, 4}, {2, 1, 4, 3}, {3, 4, 1, 2}, {4, 3, 2, 1}},
c := makeCube(from, 4), m, rm, fk
integer freq = new_dict()
for i=1 to 10000 do
c = shuffleCube(c)
m = toMatrix(c)
rm = toReduced(m)
setd(rm,getd(rm,freq)+1,freq)
end for
fk = getd_all_keys(freq)
for i=1 to length(fk) do
printf(1,"%v occurs %d times\n", {fk[i],getd(fk[i],freq)})
end for
printf(1,"\nPart 2: 10,000 latin squares of order 5 in reduced form:\n\n")
from = {{1, 2, 3, 4, 5}, {2, 3, 4, 5, 1}, {3, 4, 5, 1, 2},
{4, 5, 1, 2, 3}, {5, 1, 2, 3, 4}}
c = makeCube(from, 5)
destroy_dict(freq, justclear:=true)
for i=1 to 10000 do
c = shuffleCube(c)
m = toMatrix(c)
rm = toReduced(m)
setd(rm,getd(rm,freq)+1,freq)
end for
fk = getd_all_keys(freq)
for i=1 to length(fk) do
fk[i] = sprintf("%2d(%3d)", {i,getd(fk[i],freq)})
end for
puts(1,join_by(fk,8,7," ","\n"))
destroy_dict(freq)
-- part 3
printf(1,"\nPart 3: 750 latin squares of order 42, showing the last one:\n\n")
c = makeCube(NULL, 42)
for i=1 to 750 do
c = shuffleCube(c)
end for
m = toMatrix(c)
integer n := length(m)
for i=1 to n do
for j=1 to n do
m[i,j] = sprintf("%2d",m[i,j])
end for
m[i] = join(m[i]," ")
end for
printf(1,"%s\n",join(m,"\n"))
-- part 4
printf(1,"\nPART 4: 1000 latin squares of order 256:\n\n")
atom t0 = time()
c = makeCube(NULL, 256)
for i=1 to 1000 do
c = shuffleCube(c)
end for
printf(1,"Generated in %s\n", elapsed(time()-t0))
end procedure
main()
{{out}}
Part 1: 10,000 latin Squares of order 4 in reduced form:
{{1,2,3,4},{2,1,4,3},{3,4,1,2},{4,3,2,1}} occurs 2503 times
{{1,2,3,4},{2,1,4,3},{3,4,2,1},{4,3,1,2}} occurs 2560 times
{{1,2,3,4},{2,3,4,1},{3,4,1,2},{4,1,2,3}} occurs 2510 times
{{1,2,3,4},{2,4,1,3},{3,1,4,2},{4,3,2,1}} occurs 2427 times
Part 2: 10,000 latin squares of order 5 in reduced form:
1(172) 9(197) 17(228) 25(166) 33(171) 41(224) 49(171)
2(168) 10(162) 18(216) 26(227) 34(172) 42(155) 50(226)
3(159) 11(198) 19(206) 27(165) 35(189) 43(190) 51(174)
4(170) 12(207) 20(159) 28(166) 36(177) 44(171) 52(196)
5(211) 13(148) 21(172) 29(173) 37(183) 45(189) 53(197)
6(169) 14(163) 22(128) 30(179) 38(184) 46(138) 54(173)
7(168) 15(155) 23(146) 31(170) 39(187) 47(170) 55(206)
8(193) 16(177) 24(146) 32(176) 40(157) 48(183) 56(177)
Part 3: 750 latin squares of order 42, showing the last one:
5 29 15 7 25 26 2 35 21 39 8 12 17 31 3 20 23 22 40 34 13 32 27 38 9 6 36 41 11 19 4 42 10 28 33 18 30 16 1 14 37 24
34 17 22 12 38 28 20 42 15 10 4 3 30 16 35 23 11 19 31 8 32 1 33 36 24 2 18 39 9 41 40 26 25 27 29 5 7 37 21 13 6 14
23 14 41 38 2 36 4 34 29 16 11 10 24 13 26 31 30 12 28 18 7 21 40 42 27 9 37 35 1 3 17 22 20 5 6 33 32 39 25 19 15 8
29 21 27 41 3 10 12 23 4 18 39 1 11 6 20 34 2 35 36 37 40 5 14 26 17 42 24 33 32 16 28 8 13 30 15 9 25 19 38 7 31 22
8 32 10 17 30 15 18 13 19 6 26 29 34 42 28 40 24 23 33 7 3 4 12 37 38 36 1 21 41 20 16 25 5 11 2 39 14 22 31 35 9 27
27 40 39 16 11 23 14 20 6 4 19 28 36 12 31 24 42 10 35 33 17 18 30 3 21 5 38 15 7 1 9 34 8 32 37 13 2 26 29 22 25 41
31 39 29 22 20 6 11 17 16 19 41 36 35 33 30 14 4 2 15 24 21 10 25 1 18 12 40 28 5 37 32 27 3 13 42 38 9 34 26 8 7 23
11 33 42 28 14 7 6 24 37 26 13 35 9 5 19 18 15 20 25 41 30 17 3 12 22 8 21 27 39 10 34 40 32 36 4 31 23 29 2 38 16 1
20 11 7 8 32 31 40 37 42 13 21 22 26 2 12 29 1 27 6 14 19 41 38 17 36 25 4 5 30 15 24 35 16 34 39 3 28 23 9 18 33 10
24 9 28 40 33 29 3 7 34 11 16 27 2 30 42 25 21 13 41 10 38 8 39 35 12 26 19 20 23 31 5 32 1 22 14 6 4 15 37 36 17 18
2 8 23 37 27 9 38 36 13 24 31 14 29 7 6 42 3 34 18 32 1 20 22 41 25 30 33 16 15 4 11 10 26 39 21 28 17 40 19 5 12 35
13 2 26 15 10 40 39 6 33 29 42 34 12 17 11 28 22 32 14 25 24 37 21 5 8 23 30 9 18 7 41 31 4 3 27 19 16 35 20 1 38 36
22 23 34 31 28 25 36 38 9 32 30 8 3 11 17 41 26 39 24 6 2 35 13 4 7 21 29 18 14 27 19 37 15 20 16 12 10 33 40 42 1 5
36 28 20 11 29 39 22 41 35 7 5 15 31 24 8 19 27 37 1 38 16 13 6 2 32 40 14 25 33 17 21 4 34 23 30 10 18 42 12 9 26 3
6 25 8 2 17 33 19 12 1 38 40 39 5 32 18 7 34 30 9 11 15 3 31 23 37 24 27 14 20 28 36 16 21 42 13 29 41 4 35 10 22 26
14 24 38 32 12 3 15 2 17 28 36 40 19 26 1 27 29 41 8 5 23 42 20 13 10 34 6 31 16 35 30 7 11 18 22 21 33 25 4 37 39 9
39 30 5 20 1 22 9 40 36 27 7 33 37 18 29 38 25 42 4 21 14 31 10 28 26 15 16 8 3 13 35 19 41 2 32 24 12 11 17 23 34 6
35 18 17 14 13 41 25 31 2 3 32 24 10 19 22 33 6 1 16 23 9 15 8 39 5 7 11 12 42 34 37 28 38 4 26 20 40 36 27 21 30 29
9 19 24 26 42 16 7 30 10 40 29 4 33 8 38 22 14 25 37 28 5 27 41 32 1 13 17 36 34 39 23 11 31 6 35 2 20 21 18 15 3 12
12 22 37 1 4 20 32 3 30 25 28 26 6 14 36 11 39 21 38 29 27 24 7 16 15 31 9 34 10 33 13 18 40 35 5 17 19 8 42 41 23 2
3 16 31 42 7 17 37 25 23 36 15 18 27 22 5 21 40 9 10 39 4 26 29 6 2 33 41 19 35 8 12 20 28 38 24 32 11 1 34 30 14 13
19 41 36 34 21 18 26 29 27 20 14 16 38 40 7 15 32 3 17 4 10 28 35 33 13 22 8 6 25 42 31 23 2 37 9 30 1 12 5 24 11 39
25 4 12 29 26 37 16 9 22 30 6 23 40 21 15 35 20 38 19 42 11 2 1 18 3 41 5 10 28 36 33 39 27 24 34 8 31 32 14 17 13 7
41 12 14 33 40 35 28 15 7 9 1 5 13 23 27 32 8 17 26 31 42 34 37 19 30 38 20 22 2 6 39 21 36 29 18 16 3 24 11 4 10 25
26 20 3 19 16 30 5 14 8 41 10 7 25 15 21 13 38 36 39 22 28 23 17 27 33 37 34 32 4 2 29 12 9 31 1 42 24 18 6 40 35 11
10 1 25 36 37 24 8 26 3 12 34 42 18 38 41 16 9 14 32 35 31 30 5 22 39 27 7 4 13 29 6 15 23 19 28 11 21 2 33 20 40 17
37 35 40 13 39 8 31 33 38 15 12 32 16 41 34 6 5 11 30 27 20 22 26 14 29 18 28 23 36 21 25 2 7 1 17 4 42 9 10 3 24 19
30 34 2 24 35 1 23 10 20 42 22 37 15 39 9 17 12 4 5 26 18 38 16 29 31 3 25 11 21 14 8 41 6 40 19 7 13 27 28 32 36 33
16 7 19 21 18 27 29 22 39 35 2 38 28 20 40 9 36 8 12 1 41 33 15 31 11 10 42 24 6 32 26 17 37 14 25 23 5 13 3 34 4 30
32 3 11 25 5 12 1 4 18 31 33 19 41 9 37 10 7 24 13 40 6 16 42 21 34 20 26 2 38 22 15 14 35 17 23 36 8 30 39 27 29 28
1 13 30 39 36 4 34 32 12 14 17 6 23 27 24 3 41 40 11 20 22 9 28 15 42 16 2 29 31 5 7 33 19 21 10 35 26 38 8 25 18 37
18 38 4 23 41 19 35 21 26 33 37 20 42 28 13 5 10 7 3 15 25 39 32 9 14 17 31 40 29 24 1 36 30 8 12 34 27 6 22 11 2 16
4 27 21 3 8 42 41 16 40 37 18 2 22 25 32 36 17 5 23 30 29 6 9 34 19 35 15 13 24 11 14 1 12 10 38 26 39 20 7 33 28 31
40 26 9 30 6 21 42 19 5 2 3 31 4 35 23 37 28 15 20 13 34 12 11 8 16 14 39 17 22 25 27 38 18 33 7 1 36 10 24 29 41 32
28 15 1 4 19 11 24 5 31 8 23 17 21 34 14 26 37 18 7 2 35 29 36 10 6 39 32 30 27 38 3 9 33 16 20 25 22 41 13 12 42 40
21 10 35 27 31 2 13 39 28 5 9 41 1 36 4 8 19 29 34 16 33 40 24 25 20 11 22 7 12 18 42 30 14 26 3 37 15 17 23 6 32 38
17 42 18 6 23 5 33 1 24 34 35 30 7 37 16 12 31 26 21 19 39 14 4 11 41 32 10 3 40 9 38 13 22 25 36 27 29 28 15 2 8 20
42 6 13 35 22 32 10 8 14 21 24 11 39 1 2 4 18 33 27 9 12 25 23 40 28 29 3 26 37 30 20 5 17 41 31 15 38 7 36 16 19 34
7 36 16 5 9 34 21 11 32 22 20 25 8 10 33 30 35 31 29 12 26 19 2 24 4 1 13 38 17 23 18 6 39 15 40 14 37 3 41 28 27 42
15 37 32 9 24 38 27 28 41 17 25 13 20 29 10 39 33 6 2 36 8 7 18 30 35 4 23 1 19 26 22 3 42 12 11 40 34 14 16 31 5 21
33 31 6 18 34 14 17 27 25 1 38 21 32 4 39 2 13 16 42 3 36 11 19 7 23 28 12 37 8 40 10 29 24 9 41 22 35 5 30 26 20 15
38 5 33 10 15 13 30 18 11 23 27 9 14 3 25 1 16 28 22 17 37 36 34 20 40 19 35 42 26 12 2 24 29 7 8 41 6 31 32 39 21 4
PART 4: 1000 latin squares of order 256:
Generated in 19.5s
Unfortunately the last part of this task exposes the relatively poor performance of subscripting in phix.