| |||||||||
Branching strategies Description Branching schemes for the
enumeration of decision variables (discrete or continuous), disjunctive constraints, or tasks can be configured to use
built-in or user-defined variable / constraint / task and value selection heuristics.
Source Files By clicking on a file name, a preview is opened at the bottom of this page. probeac2001_nary.mos (!**************************************************************** CP example problems =================== file probeac2001_nary.mos ````````````````````````` Euler knight tour problem implemented with user-defined binary constraints. -- n-ary formulation version -- *** This model cannot be run with a Community Licence for the default data instance *** (c) 2008 Artelys S.A. and Fair Isaac Corporation Creation: May 2005, rev. Jul. 2022 *****************************************************************!) 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) forward function valid_knight_move(vals: cptuple, s: integer): boolean declarations PATH = 1..N ! Cells on the board pos: array(PATH) of cpvar ! Position p in tour propagation : integer ! Alg choice: 0, 1, or 2 end-declarations ! Selecting the propagation algorithm for the generic nary constraint propagation := 0 ! 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_nary_constraint({pos(i), pos(i+1)}, ->valid_knight_move,propagation,S) generic_nary_constraint({pos(N), pos(1)}, ->valid_knight_move,propagation,S) ! 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(vals: cptuple, s: integer): boolean declarations xa,ya,xb,yb,delta_x,delta_y: integer a,b : integer end-declarations ! Current position data a := getelt(vals,1) ! 1 : pos(i) b := getelt(vals,2) ! 2 : pos(i+1) 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 | |||||||||
© Copyright 2024 Fair Isaac Corporation. |