(!**************************************************************** CP example problems =================== file probeac2001.mos ```````````````````` Euler knight tour problem implemented with user-defined binary constraints. (c) 2008 Artelys S.A. and Fair Isaac Corporation Creation: 2005, rev. Mar. 2013 *****************************************************************!) model "Euler Knight Moves" uses "kalis" parameters S = 8 ! No. of rows/columns end-parameters N:= S * S ! Total number of cells setparam("KALIS_DEFAULT_LB", 0) setparam("KALIS_DEFAULT_UB", N-1) declarations PATH = 1..N ! Cells on the board pos: array(PATH) of cpvar ! Position p in tour end-declarations ! Setting names of decision variables forall(i in PATH) setname(pos(i), "Position"+i) ! Fix the start position pos(1) = 0 ! Each cell is visited once all_different(pos, KALIS_GEN_ARC_CONSISTENCY) ! The knight's path obeys the chess rules for valid knight moves forall(i in 1..N-1) generic_binary_constraint(pos(i), pos(i+1), "valid_knight_move") generic_binary_constraint(pos(N), pos(1), "valid_knight_move") ! Setting enumeration parameters cp_set_branching(probe_assign_var(KALIS_SMALLEST_MIN, KALIS_MAX_TO_MIN, pos, 14)) ! Search for up to NBSOL solutions solct:= 0 if not cp_find_next_sol then writeln("No solution") else writeln(pos) end-if ! **** Test whether the move from a to b is admissible **** function valid_knight_move(a:integer, b:integer): boolean declarations xa,ya,xb,yb,delta_x,delta_y: integer end-declarations xa := a div S ya := a mod S xb := b div S yb := b mod S delta_x := abs(xa-xb) delta_y := abs(ya-yb) returned := (delta_x<=2) and (delta_y<=2) and (delta_x+delta_y=3) end-function end-model