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288 | with Ada.Calendar;
with Ada.Command_Line;
with Ada.Text_IO; use Ada.Text_IO;
with Ada.Numerics.Discrete_Random;
with AdaSAT.Builders;
with AdaSAT.DPLL;
with AdaSAT.Formulas;
with AdaSAT.Theory;
procedure WFC is
use Ada.Calendar;
use AdaSAT;
use AdaSAT.Formulas;
Print_Steps : constant Boolean := False;
-- Set to True to print the generated map at each decision routine
-- invocation. Useful for debug and visualization of the algorithm.
N : constant := 9;
-- size of the resulting image
T : constant := 5;
-- Number of tile kinds
type Tile_Kind is ('0', 'x', '^', '_', ' ');
type Direction_Kind is (Top, Down, Left, Right);
type Tile_Kind_Array is array (Positive range <>) of Tile_Kind;
type Adjacency_Matrix is array
(Tile_Kind, Direction_Kind, Tile_Kind) of Boolean;
-- encodes which tile kind is allowed or forbidden as the neighbor
-- of the given tile kind in the given which direction.
package Natural_Randoms is new Ada.Numerics.Discrete_Random (Natural);
Rnd : Natural_Randoms.Generator;
function Transform (I, J : Natural; K : Tile_Kind) return Variable is
(Variable ((I - 1) * N * T + (J - 1) * T + Tile_Kind'Pos (K) + 1));
-- The the boolean variable representing 'cell at coords (I, J) is of
-- tile kind K).
function Get_Neighbour
(I, J : Natural;
D : Direction_Kind;
X, Y : out Natural) return Boolean;
function Get_Neighbour
(I, J : Natural;
D : Direction_Kind;
X, Y : out Natural) return Boolean
is
begin
case D is
when Top =>
if J = 1 then
return False;
else
X := I;
Y := J - 1;
end if;
when Down =>
if J = N then
return False;
else
X := I;
Y := J + 1;
end if;
when Left =>
if I = 1 then
return False;
else
X := I - 1;
Y := J;
end if;
when Right =>
if I = N then
return False;
else
X := I + 1;
Y := J;
end if;
end case;
return True;
end Get_Neighbour;
function Image (K : Tile_Kind) return String;
function Image (K : Tile_Kind) return String is
Img : String := K'Image;
begin
return Img (2 .. 2);
end Image;
type Empty_Context is null record;
C : Empty_Context;
function Empty_Theory_Check
(Ctx : in out Empty_Context;
M : Model;
F : in out Formula) return Boolean;
function Empty_Theory_Check
(Ctx : in out Empty_Context;
M : Model;
F : in out Formula) return Boolean
is
pragma Unreferenced (Ctx, M, F);
begin
return True;
end Empty_Theory_Check;
package Empty_Theory is new Theory (Empty_Context, Empty_Theory_Check);
function Least_Entropy_Decision
(M : Model; First_Unset : in out Variable) return Variable_Or_Null;
procedure Print_Map (M : Model);
procedure Print_Map (M : Model) is
Unset : Boolean;
begin
for J in 1 .. N loop
for I in 1 .. N loop
Unset := True;
for K in Tile_Kind loop
if M (Transform (I, J, K)) in True then
Put (Image (K));
Unset := False;
exit;
end if;
end loop;
if Unset then
Put ('?');
end if;
end loop;
New_Line;
end loop;
New_Line;
end Print_Map;
function Least_Entropy_Decision
(M : Model; First_Unset : in out Variable) return Variable_Or_Null
is
Best_Cell_X, Best_Cell_Y : Natural := 1;
Best_Cell_Unset_Count : Natural := T + 1;
Cur_Cell_Unset_Count : Natural;
Chosen_Tile : Natural;
begin
if Print_Steps then
Print_Map (M);
end if;
for J in 1 .. N loop
for I in 1 .. N loop
Cur_Cell_Unset_Count := 0;
for K in Tile_Kind loop
if M (Transform (I, J, K)) in Unset then
Cur_Cell_Unset_Count := Cur_Cell_Unset_Count + 1;
end if;
end loop;
if Cur_Cell_Unset_Count > 0 then
-- todo change <= to < and handle = specially
if Cur_Cell_Unset_Count <= Best_Cell_Unset_Count then
Best_Cell_X := I;
Best_Cell_Y := J;
Best_Cell_Unset_Count := Cur_Cell_Unset_Count;
end if;
end if;
if Print_Steps then
Put (Cur_Cell_Unset_Count'Image);
end if;
end loop;
if Print_Steps then
New_Line;
end if;
end loop;
if Print_Steps then
New_Line;
New_Line;
New_Line;
end if;
Chosen_Tile := Natural_Randoms.Random (Rnd) mod Best_Cell_Unset_Count;
for K in Tile_Kind loop
if M (Transform (Best_Cell_X, Best_Cell_Y, K)) in Unset then
if Chosen_Tile = 0 then
return Transform (Best_Cell_X, Best_Cell_Y, K);
else
Chosen_Tile := Chosen_Tile - 1;
end if;
end if;
end loop;
raise Program_Error;
end Least_Entropy_Decision;
package SAT is new DPLL (Empty_Theory, Least_Entropy_Decision);
F : Builders.Formula_Builder;
Adjacency_Rules : Adjacency_Matrix :=
(others => (others => (others => True)));
Sol : Model := [1 .. N * N * T => Unset];
begin
-- Setup problem specific adjacency rules
Adjacency_Rules ('0', Top, '0') := False;
Adjacency_Rules ('0', Top, 'x') := False;
Adjacency_Rules ('0', Left, '^') := False;
Adjacency_Rules ('0', Right, '^') := False;
Adjacency_Rules ('0', Left, ' ') := False;
Adjacency_Rules ('0', Right, ' ') := False;
Adjacency_Rules ('x', Top, '0') := False;
Adjacency_Rules ('^', Top, '0') := False;
Adjacency_Rules ('^', Top, 'x') := False;
Adjacency_Rules ('^', Left, 'x') := False;
Adjacency_Rules ('^', Right, 'x') := False;
Adjacency_Rules (' ', Down, '0') := False;
Adjacency_Rules (' ', Left, 'x') := False;
Adjacency_Rules (' ', Right, 'x') := False;
Adjacency_Rules (' ', Top, '0') := False;
Adjacency_Rules (' ', Top, '^') := False;
Adjacency_Rules (' ', Top, 'x') := False;
for K in Tile_Kind loop
Adjacency_Rules ('_', Down, K) := False;
Adjacency_Rules ('_', Left, K) := False;
Adjacency_Rules ('_', Right, K) := False;
end loop;
Adjacency_Rules ('_', Left, '_') := True;
Adjacency_Rules ('_', Right, '_') := True;
-- Uncomment the following line to get a random output.
-- Natural_Randoms.Reset (Rnd, Integer (Seconds (Clock)));
-- Add the constraint that each cell must be only one tile
for I in 1 .. N loop
for J in 1 .. N loop
declare
C : Builders.Clause_Builder;
begin
for K in Tile_Kind loop
C.Add (+Transform (I, J, K));
end loop;
F.Add (C.Build);
F.Add_At_Most_One
(Transform (I, J, Tile_Kind'First),
Transform (I, J, Tile_Kind'Last));
end;
end loop;
end loop;
-- Setup the adjacency constraints
for I in 1 .. N loop
for J in 1 .. N loop
for D in Direction_Kind loop
declare
X, Y : Natural;
C : Builders.Clause_Builder;
begin
if Get_Neighbour (I, J, D, X, Y) then
for K_1 in Tile_Kind loop
C.Add (-Transform (I, J, K_1));
for K_2 in Tile_Kind loop
if Adjacency_Rules (K_1, D, K_2) then
C.Add (+Transform (X, Y, K_2));
else
F.Add (new Literal_Array'
(-Transform (I, J, K_1),
-Transform (X, Y, K_2)));
end if;
end loop;
F.Add (C.Build);
end loop;
end if;
end;
end loop;
end loop;
end loop;
if SAT.Solve (F.Build, C, Sol) then
Put_Line ("Solved");
else
Put_Line ("Failed solving");
end if;
Print_Map (Sol);
end WFC;
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