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			128 lines
		
	
	
	
		
			3.4 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
			
		
		
	
	
			128 lines
		
	
	
	
		
			3.4 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
from z3 import *
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class Car():
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    def __init__(self, is_vertical, base_pos, length, start, color):
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        self.is_vertical = is_vertical          
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        self.base = base_pos
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        self.length = length
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        self.start = start
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        self.color = color
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    def __eq__(self, other):
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        return self.color == other.color
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    def __ne__(self, other):
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        return self.color != other.color
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dimension = 6
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red_car = Car(False, 2, 2, 3, "red")
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cars = [
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    Car(True, 0, 3, 0, 'yellow'),
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    Car(False, 3, 3, 0, 'blue'),
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    Car(False, 5, 2, 0, "brown"),
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    Car(False, 0, 2, 1, "lgreen"),
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    Car(True,  1, 2, 1, "light blue"),
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    Car(True,  2, 2, 1, "pink"),
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    Car(True,  2, 2, 4, "dark green"),
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    red_car,
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    Car(True,  3, 2, 3, "purple"),
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    Car(False, 5, 2, 3, "light yellow"),
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    Car(True,  4, 2, 0, "orange"),
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    Car(False, 4, 2, 4, "black"),
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    Car(True,  5, 3, 1, "light purple")
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    ]
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num_cars = len(cars)
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B = BoolSort()
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bv3 = BitVecSort(3)
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state = Function('state', [ bv3 for c in cars] + [B])
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def num(i):
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    return BitVecVal(i,bv3)
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def bound(i):
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    return Const(cars[i].color, bv3)
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fp = Fixedpoint()
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fp.set("fp.engine","datalog")
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fp.set("datalog.generate_explanations",True)
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fp.declare_var([bound(i) for i in range(num_cars)])
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fp.register_relation(state)
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def mk_state(car, value):
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    return state([ (num(value) if (cars[i] == car) else bound(i)) for i in range(num_cars)])
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def mk_transition(row, col, i0, j, car0):
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    body = [mk_state(car0, i0)]
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    for index in range(num_cars):
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        car = cars[index]
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        if car0 != car:
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            if car.is_vertical and car.base == col:
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                for i in range(dimension):
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                    if i <= row and row < i + car.length and i + car.length <= dimension:
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                        body += [bound(index) != num(i)]
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            if car.base == row and not car.is_vertical:
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                for i in range(dimension):
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                    if i <= col and col < i + car.length and i + car.length <= dimension:
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                        body += [bound(index) != num(i)]
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    s = "%s %d->%d" % (car0.color, i0, j)
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    fp.rule(mk_state(car0, j), body, s)
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def move_down(i, car):
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    free_row = i + car.length
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    if free_row < dimension:
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        mk_transition(free_row, car.base, i, i + 1, car)
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def move_up(i, car):
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    free_row = i  - 1
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    if 0 <= free_row and i + car.length <= dimension:
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        mk_transition(free_row, car.base, i, i - 1, car)
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def move_left(i, car):
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    free_col = i - 1;
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    if 0 <= free_col and i + car.length <= dimension:
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        mk_transition(car.base, free_col, i, i - 1, car)
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def move_right(i, car):
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    free_col = car.length + i
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    if free_col < dimension:
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        mk_transition(car.base, free_col, i, i + 1, car)
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# Initial state:
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fp.fact(state([num(cars[i].start) for i in range(num_cars)]))
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# Transitions:
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for car in cars:
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    for i in range(dimension):
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        if car.is_vertical:
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            move_down(i, car)
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            move_up(i, car)
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        else:
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            move_left(i, car)
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            move_right(i, car)
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def get_instructions(ans):
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    lastAnd = ans.arg(0).children()[-1]
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    trace = lastAnd.children()[1]
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    while trace.num_args() > 0:
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        print(trace.decl())
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        trace = trace.children()[-1]
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goal = state([ (num(4) if cars[i] == red_car else bound(i)) for i in range(num_cars)])
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fp.query(goal)
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get_instructions(fp.get_answer())
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del goal
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del state
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del fp
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