def remove(self, superitem):
"""
Return a new layer without the given superitem
"""
new_spool = superitems.SuperitemPool(
superitems=[s for s in self.superitems_pool if s != superitem])
new_scoords = [
c for i, c in enumerate(self.superitems_coords)
if i != self.superitems_pool.get_index(superitem)
]
return Layer(new_spool, new_scoords, self.pallet_dims)
def _get_new_layer(to_place):
"""
Place the maximum amount of items that can fit in
a new layer, starting from the given pool
"""
assert len(
to_place) > 0, "The number of superitems to place must be > 0"
spool = superitems.SuperitemPool(superitems=to_place)
layer = maxrects.maxrects_single_layer_online(
spool, self.pallet_dims)
return layer
def not_covered_superitems(self):
"""
Return a list of superitems which are not present in any layer
"""
covered_spool = superitems.SuperitemPool(superitems=None)
for l in self.layers:
covered_spool.extend(l.superitems_pool)
return [
s for s in self.superitems_pool
if covered_spool.get_index(s) is None
]
def _add_single_layers(self):
"""
Add one layer for each superitem that only
contains that superitem
"""
for superitem in self.superitems_pool:
self.add(
Layer(
superitems.SuperitemPool([superitem]),
[utils.Coordinate(x=0, y=0)],
self.pallet_dims,
))
def maxrects_single_layer_offline(superitems_pool,
pallet_dims,
superitems_in_layer=None):
"""
Given a superitems pool and the maximum dimensions to pack them into,
try to fit each superitem in a single layer (if not possible, return an error)
"""
logger.debug("MR-SL-Offline starting")
# Set all superitems in layer
if superitems_in_layer is None:
superitems_in_layer = np.arange(len(superitems_pool))
logger.debug(
f"MR-SL-Offline {superitems_in_layer}/{len(superitems_pool)} superitems to place"
)
# Iterate over each placement strategy
ws, ds, _ = superitems_pool.get_superitems_dims()
for strategy in MAXRECTS_PACKING_STRATEGIES:
# Create the maxrects packing algorithm
packer = newPacker(
mode=PackingMode.Offline,
bin_algo=PackingBin.Global,
pack_algo=strategy,
sort_algo=SORT_AREA,
rotation=False,
)
# Add one bin representing one layer
packer.add_bin(pallet_dims.width, pallet_dims.depth, count=1)
# Add superitems to be packed
for i in superitems_in_layer:
packer.add_rect(ws[i], ds[i], rid=i)
# Start the packing procedure
packer.pack()
# Feasible packing with a single layer
if len(packer) == 1 and len(packer[0]) == len(superitems_in_layer):
spool = superitems.SuperitemPool(
superitems=[superitems_pool[s.rid] for s in packer[0]])
layer = layers.Layer(
spool, [utils.Coordinate(s.x, s.y) for s in packer[0]],
pallet_dims)
logger.debug(
f"MR-SL-Offline generated a new layer with {len(layer)} superitems "
f"and {layer.get_density(two_dims=False)} 3D density")
return layer
return None
def build_layer_from_model_output(superitems_pool, superitems_in_layer,
solution, pallet_dims):
"""
Return a single layer from the given model solution (either baseline or column generation).
The 'solution' parameter should be a dictionary of the form
{
'c_{s}_x': ...,
'c_{s}_y: ...,
...
}
"""
spool, scoords = [], []
for s in superitems_in_layer:
spool += [superitems_pool[s]]
scoords += [Coordinate(x=solution[f"c_{s}_x"], y=solution[f"c_{s}_y"])]
spool = superitems.SuperitemPool(superitems=spool)
return layers.Layer(spool, scoords, pallet_dims)
def get_height_groups(superitems_pool,
pallet_dims,
height_tol=0,
density_tol=0.5):
"""
Divide the whole pool of superitems into groups having either
the exact same height or an height within the given tolerance
"""
assert height_tol >= 0 and density_tol >= 0.0, "Tolerance parameters must be non-negative"
# Get unique heights
unique_heights = sorted(set(s.height for s in superitems_pool))
height_sets = {
h: {k
for k in unique_heights[i:] if k - h <= height_tol}
for i, h in enumerate(unique_heights)
}
for (i, hi), (j, hj) in zip(
list(height_sets.items())[:-1],
list(height_sets.items())[1:]):
if hj.issubset(hi):
unique_heights.remove(j)
# Generate one group of superitems for each similar height
groups = []
for height in unique_heights:
spool = [
s for s in superitems_pool
if s.height >= height and s.height <= height + height_tol
]
spool = superitems.SuperitemPool(superitems=spool)
if (sum(s.volume
for s in spool) >= density_tol * spool.get_max_height() *
pallet_dims.width * pallet_dims.depth):
groups += [spool]
return groups
def maxrects_single_layer_online(superitems_pool,
pallet_dims,
superitems_duals=None):
"""
Given a superitems pool and the maximum dimensions to pack them into, try to fit
the greatest number of superitems in a single layer following the given order
"""
logger.debug("MR-SL-Online starting")
# If no duals are given use superitems' heights as a fallback
ws, ds, hs = superitems_pool.get_superitems_dims()
if superitems_duals is None:
superitems_duals = np.array(hs)
# Sort rectangles by duals
indexes = utils.argsort(list(zip(superitems_duals, hs)), reverse=True)
logger.debug(
f"MR-SL-Online {sum(superitems_duals[i] > 0 for i in indexes)} non-zero duals to place"
)
# Iterate over each placement strategy
generated_layers, num_duals = [], []
for strategy in MAXRECTS_PACKING_STRATEGIES:
# Create the maxrects packing algorithm
packer = newPacker(
mode=PackingMode.Online,
pack_algo=strategy,
rotation=False,
)
# Add one bin representing one layer
packer.add_bin(pallet_dims.width, pallet_dims.depth, count=1)
# Online packing procedure
n_packed, non_zero_packed, layer_height = 0, 0, 0
for i in indexes:
if superitems_duals[i] > 0 or hs[i] <= layer_height:
packer.add_rect(ws[i], ds[i], i)
if len(packer[0]) > n_packed:
n_packed = len(packer[0])
if superitems_duals[i] > 0:
non_zero_packed += 1
if hs[i] > layer_height:
layer_height = hs[i]
num_duals += [non_zero_packed]
# Build layer after packing
spool, coords = [], []
for s in packer[0]:
spool += [superitems_pool[s.rid]]
coords += [utils.Coordinate(s.x, s.y)]
layer = layers.Layer(superitems.SuperitemPool(spool), coords,
pallet_dims)
generated_layers += [layer]
# Find the best layer by taking into account the number of
# placed superitems with non-zero duals and density
layer_indexes = utils.argsort(
[(duals, layer.get_density(two_dims=False))
for duals, layer in zip(num_duals, generated_layers)],
reverse=True,
)
layer = generated_layers[layer_indexes[0]]
logger.debug(
f"MR-SL-Online generated a new layer with {len(layer)} superitems "
f"(of which {num_duals[layer_indexes[0]]} with non-zero dual) "
f"and {layer.get_density(two_dims=False)} 3D density")
return layer
def maxrects_multiple_layers(superitems_pool, pallet_dims, add_single=True):
"""
Given a superitems pool and the maximum dimensions to pack them into,
return a layer pool with warm start placements
"""
logger.debug("MR-ML-Offline starting")
logger.debug(
f"MR-ML-Offline {'used' if add_single else 'not_used'} as warm_start")
logger.debug(f"MR-ML-Offline {len(superitems_pool)} superitems to place")
# Return a layer with a single item if only one is present in the superitems pool
if len(superitems_pool) == 1:
layer_pool = layers.LayerPool(superitems_pool,
pallet_dims,
add_single=True)
uncovered = 0
else:
generated_pools = []
for strategy in MAXRECTS_PACKING_STRATEGIES:
# Build initial layer pool
layer_pool = layers.LayerPool(superitems_pool,
pallet_dims,
add_single=add_single)
# Create the maxrects packing algorithm
packer = newPacker(
mode=PackingMode.Offline,
bin_algo=PackingBin.Global,
pack_algo=strategy,
sort_algo=SORT_AREA,
rotation=False,
)
# Add an infinite number of layers (no upper bound)
packer.add_bin(pallet_dims.width,
pallet_dims.depth,
count=float("inf"))
# Add superitems to be packed
ws, ds, _ = superitems_pool.get_superitems_dims()
for i, (w, d) in enumerate(zip(ws, ds)):
packer.add_rect(w, d, rid=i)
# Start the packing procedure
packer.pack()
# Build a layer pool
for layer in packer:
spool, scoords = [], []
for superitem in layer:
spool += [superitems_pool[superitem.rid]]
scoords += [utils.Coordinate(superitem.x, superitem.y)]
spool = superitems.SuperitemPool(superitems=spool)
layer_pool.add(layers.Layer(spool, scoords, pallet_dims))
layer_pool.sort_by_densities(two_dims=False)
# Add the layer pool to the list of generated pools
generated_pools += [layer_pool]
# Find the best layer pool by considering the number of placed superitems,
# the number of generated layers and the density of each layer dense
uncovered = [
len(pool.not_covered_superitems()) for pool in generated_pools
]
n_layers = [len(pool) for pool in generated_pools]
densities = [
pool[0].get_density(two_dims=False) for pool in generated_pools
]
pool_indexes = utils.argsort(list(zip(uncovered, n_layers, densities)),
reverse=True)
layer_pool = generated_pools[pool_indexes[0]]
uncovered = uncovered[pool_indexes[0]]
logger.debug(
f"MR-ML-Offline generated {len(layer_pool)} layers with 3D densities {layer_pool.get_densities(two_dims=False)}"
)
logger.debug(
f"MR-ML-Offline placed {len(superitems_pool) - uncovered}/{len(superitems_pool)} superitems"
)
return layer_pool
def _place_not_covered(self, singles_removed=None, area_tol=1.0):
"""
Place the remaining items (not superitems) either on top
of existing bins or in a whole new bin, if they do not fit
"""
def _get_unplaceable_items(superitems_list, max_spare_height):
"""
Return items that must be placed in a new bin
"""
index = len(superitems_list)
for i, s in enumerate(superitems_list):
if s.height > max_spare_height:
index = i
break
return superitems_list[:index], superitems_list[index:]
def _get_placeable_items(superitems_list, working_bin):
"""
Return items that can be placed in a new layer
in the given bin
"""
to_place = []
for s in superitems_list:
last_layer_area = working_bin.layer_pool[-1].area
max_area = np.clip(area_tol * last_layer_area, 0,
self.pallet_dims.area)
area = sum(s.area for s in to_place)
if area < max_area and s.height < working_bin.remaining_height:
to_place += [s]
else:
break
return to_place
def _get_new_layer(to_place):
"""
Place the maximum amount of items that can fit in
a new layer, starting from the given pool
"""
assert len(
to_place) > 0, "The number of superitems to place must be > 0"
spool = superitems.SuperitemPool(superitems=to_place)
layer = maxrects.maxrects_single_layer_online(
spool, self.pallet_dims)
return layer
def _place_new_layers(superitems_list, remaining_heights):
"""
Try to place items in the bin with the least spare height
and fallback to the other open bins, if the layer doesn't fit
"""
sorted_indices = utils.argsort(remaining_heights)
working_index = 0
while len(superitems_list) > 0 and working_index < len(self.bins):
working_bin = self.bins[sorted_indices[working_index]]
to_place = _get_placeable_items(superitems_list, working_bin)
if len(to_place) > 0:
layer = _get_new_layer(to_place)
self.layer_pool.add(layer)
working_bin.add(layer)
for s in layer.superitems_pool:
superitems_list.remove(s)
else:
working_index = working_index + 1
return superitems_list
# Get single superitems that are not yet covered
# (assuming that the superitems pool in the layer pool contains all single superitems)
superitems_list = self.layer_pool.not_covered_single_superitems(
singles_removed=singles_removed)
# Sort superitems by ascending height
superitems_list = [
superitems_list[i]
for i in utils.argsort([s.height for s in superitems_list])
]
# Get placeable and unplaceable items
remaining_heights = self.get_remaining_heights()
max_remaining_height = 0 if len(remaining_heights) == 0 else max(
remaining_heights)
superitems_list, remaining_items = _get_unplaceable_items(
superitems_list, max_remaining_height)
superitems_list = _place_new_layers(superitems_list, remaining_heights)
# Place unplaceable items in a new bin
remaining_items += superitems_list
if len(remaining_items) > 0:
spool = superitems.SuperitemPool(superitems=remaining_items)
lpool = maxrects.maxrects_multiple_layers(spool,
self.pallet_dims,
add_single=False)
self.layer_pool.extend(lpool)
self.bins += self._build(lpool)
def main(
order,
procedure="cg",
max_iters=1,
superitems_horizontal=True,
superitems_horizontal_type="two-width",
superitems_max_vstacked=4,
density_tol=0.5,
filtering_two_dims=False,
filtering_max_coverage_all=3,
filtering_max_coverage_single=3,
tlim=None,
enable_solver_output=False,
height_tol=0,
cg_use_height_groups=True,
cg_mr_warm_start=True,
cg_max_iters=100,
cg_max_stag_iters=20,
cg_sp_mr=False,
cg_sp_np_type="mip",
cg_sp_p_type="cp",
cg_return_only_last=False,
):
"""
External interface to all the implemented solutions to solve 3D-BPP
"""
assert max_iters > 0, "The number of maximum iteration must be > 0"
assert procedure in ("mr", "bl", "cg"), "Unsupported procedure"
logger.info(f"{procedure.upper()} procedure starting")
# Create the final superitems pool and a copy of the order
final_layer_pool = layers.LayerPool(superitems.SuperitemPool(),
config.PALLET_DIMS)
working_order = order.copy()
# Iterate the specified number of times in order to reduce
# the number of uncovered items at each iteration
not_covered, all_singles_removed = [], []
for iter in range(max_iters):
logger.info(f"{procedure.upper()} iteration {iter + 1}/{max_iters}")
# Create the superitems pool and call the baseline procedure
superitems_list, singles_removed = superitems.SuperitemPool.gen_superitems(
order=working_order,
pallet_dims=config.PALLET_DIMS,
max_vstacked=superitems_max_vstacked,
horizontal=superitems_horizontal,
horizontal_type=superitems_horizontal_type,
)
superitems_pool = superitems.SuperitemPool(superitems=superitems_list)
all_singles_removed += singles_removed
# Call the right packing procedure
if procedure == "bl":
layer_pool = baseline.baseline(superitems_pool,
config.PALLET_DIMS,
tlim=tlim)
elif procedure == "mr":
layer_pool = maxrects_warm_start(superitems_pool,
height_tol=height_tol,
density_tol=density_tol,
add_single=False)
elif procedure == "cg":
layer_pool = cg(
superitems_pool,
height_tol=height_tol,
density_tol=density_tol,
use_height_groups=cg_use_height_groups,
mr_warm_start=cg_mr_warm_start,
max_iters=cg_max_iters,
max_stag_iters=cg_max_stag_iters,
tlim=tlim,
sp_mr=cg_sp_mr,
sp_np_type=cg_sp_np_type,
sp_p_type=cg_sp_p_type,
return_only_last=cg_return_only_last,
enable_solver_output=enable_solver_output,
)
# Filter layers based on the given parameters
layer_pool = layer_pool.filter_layers(
min_density=density_tol,
two_dims=filtering_two_dims,
max_coverage_all=filtering_max_coverage_all,
max_coverage_single=filtering_max_coverage_single,
)
# Add only the filtered layers
final_layer_pool.extend(layer_pool)
# Compute the number of uncovered Items
prev_not_covered = len(not_covered)
item_coverage = final_layer_pool.item_coverage()
not_covered = [k for k, v in item_coverage.items() if not v]
logger.info(
f"Items not covered: {len(not_covered)}/{len(item_coverage)}")
if len(not_covered) == prev_not_covered:
logger.info(
"Stop iterating, no improvement from the previous iteration")
break
# Compute a new order composed of only not covered items
working_order = order.iloc[not_covered].copy()
# Build a pool of bins from the layer pool and compact
# all layers in each bin to avoid having "flying" products
bin_pool = bins.BinPool(final_layer_pool,
config.PALLET_DIMS,
singles_removed=set(all_singles_removed))
return bins.CompactBinPool(bin_pool)
