def edist_grid(fline, walls):
global grid, g_metric, g_fline, g_walls, xmax, ymax
xmax = max([max(x, x1) for ((x, y), (x1, y1)) in walls])
ymax = max([max(y, y1) for ((x, y), (x1, y1)) in walls])
grid = [[edistw_to_line((x, y), fline, walls) for y in range(ymax + 1)]
for x in range(xmax + 1)]
flag = True
print('computing edist grid', end=' ')
sys.stdout.flush()
while flag:
print('.', end='')
sys.stdout.flush()
flag = False
for x in range(xmax + 1):
for y in range(ymax + 1):
for y1 in range(max(0, y - 1), min(ymax + 1, y + 2)):
for x1 in range(max(0, x - 1), min(xmax + 1, x + 2)):
if grid[x1][y1] != infinity and not racetrack.crash(
((x, y), (x1, y1)), walls):
if x == x1 or y == y1:
d = grid[x1][y1] + 1
else:
d = grid[x1][y1] + 1.4142135623730951
if d < grid[x][y]:
grid[x][y] = d
flag = True
print(' done')
g_metric = 'edist'
g_fline = fline
g_walls = walls
return grid
def xymax_grid(fline, walls):
global grid, g_metric, g_fline, g_walls, xmax, ymax
xmax = max([max(x, x1) for ((x, y), (x1, y1)) in walls])
ymax = max([max(y, y1) for ((x, y), (x1, y1)) in walls])
grid = [[xymaxw_to_line((x, y), fline, walls) for y in range(ymax + 1)]
for x in range(xmax + 1)]
flag = True
print('computing xymax grid', end=' ')
sys.stdout.flush()
while flag:
print('.', end='')
sys.stdout.flush()
flag = False
for x in range(xmax + 1):
for y in range(ymax + 1):
for y1 in range(max(0, y - 1), min(ymax + 1, y + 2)):
for x1 in range(max(0, x - 1), min(xmax + 1, x + 2)):
if grid[x1][y1] != infinity and not racetrack.crash(
((x, y), (x1, y1)), walls):
d = grid[x1][y1] + max(abs(x - x1), abs(y - y1))
if d < grid[x][y]:
grid[x][y] = d
flag = True
print(' done')
g_metric = 'xymax'
g_fline = fline
g_walls = walls
return grid
def edistw_to_line(point, edge, walls):
"""
straight-line distance from (x,y) to the line ((x1,y1),(x2,y2)).
Return infinity if there's no way to do it without intersecting a wall
"""
# if min(x1,x2) <= x <= max(x1,x2) and min(y1,y2) <= y <= max(y1,y2):
# return 0
(x, y) = point
((x1, y1), (x2, y2)) = edge
if x1 == x2:
ds = [math.sqrt((x1-x)**2 + (y3-y)**2) \
for y3 in range(min(y1,y2),max(y1,y2)+1) \
if not racetrack.crash(((x,y),(x1,y3)), walls)]
else:
ds = [math.sqrt((x3-x)**2 + (y1-y)**2) \
for x3 in range(min(x1,x2),max(x1,x2)+1) \
if not racetrack.crash(((x,y),(x3,y1)), walls)]
ds.append(infinity)
return min(ds)
def h_h2(state,
fline,
walls,
metric='edist',
crash_aware=True,
fline_aware=True):
global g_metric, g_fline, g_walls
if fline != g_fline or walls != g_walls or metric != g_metric:
# if fline != g_fline: print('fline = ', fline, '; g_fline =', g_fline)
# if walls != g_walls: print('walls different')
# if metric != g_metric: print('metric = ', metric, '; g_metric =', g_metric)
if metric == 'edist':
edist_grid(fline, walls)
elif metric == 'xymax':
xymax_grid(fline, walls)
else:
raise RuntimeError("'" + metric + "' is not a known metric")
((x, y), (u, v)) = state
hval = float(grid[x][y])
if crash_aware or fline_aware:
penalty = 0
# compute stopping distance
au = abs(u)
av = abs(v)
sdu = au * (au - 1) / 2.0
sdv = av * (av - 1) / 2.0
sd = max(sdu, sdv)
# compute location after fastest stop
if u < 0: sdu = -sdu
if v < 0: sdv = -sdv
sx = x + sdu
sy = y + sdv
if crash_aware:
if racetrack.crash([(x, y), (sx, sy)], walls):
if metric == 'edist': penalty += math.sqrt(au**2 + av**2)
elif metric == 'xymax': penalty += max(au, av)
if fline_aware:
penalty += sd / 10.0
hval = max(hval + penalty, sd)
return hval