Essence' description of PSSSODLS.

psssodls.eprime

language ESSENCE' 1.0
given     n : int
letting   Indices be domain int(0..n-1)
letting   Symbols be domain int(0..n-1)
letting   symbol_sum be (n*(n-1)/2)

find      P: matrix indexed by [Indices, Indices] of Symbols

such that
  $ all rows have to be different
  forAll row : Indices .
    allDiff(P[row,..]),

  $ all columns have to be different
  forAll col : Indices .
    allDiff(P[..,col]),

  $ pandiagonality constraints
  forAll w : Indices .
    (sum i: Indices . 
      P[i, (i + w) % n]) = symbol_sum /\
    (sum i: Indices . 
      P[i, (w - i) % n]) = symbol_sum ,

  $ strongly-symmetric constraints
  forAll i,j : Indices .
    P[i, j] + P[n - 1 - i, n - 1 - j] = n - 1,

  $ orthogonality constraints
  forAll i,j,k,l : Indices .
    i<k \/ j<l ->  P[i,j] != P[k,l] \/ P[j,i] != P[l,k]

psssodls.param

language ESSENCE' 1.0
letting n be 8