binpacker

Generic Bin Packing Problem Solver.

Given a set of items with weight information and capacity of a bin, Binpacker determines which items can fit in the bin with that capacity and continues to pack all items in new bins in a way that it will utilize the space of each bin. In the other word, Binpacker can be used to determine what is the minimum number of bins we can use to pack all items with different weights.

Requirements

• Python 3.4 (tested)

Goal

The ultimate goal of this library is to provide a generic interface for solving the Bin Packing problem for variety of applications.

Code sample

Lets say, given the capacity (11) of a bin and a list of packages with different weights, we would like to load and unload the packages in a way that it utilizes the space of each bin.

import time
from binpacker.binpacker import Binpacker
from binpacker.binpacker import Item
packer = Binpacker(11)
packer.items = [
    Item('A',4), Item('B',1), Item('C',2),
    Item('D',6), Item('E',9), Item('F',3),
    Item('G',7), Item('H',2), Item('I',5)
]
j=0
while True:
  packer.pack_items()
  for i, x in enumerate(packer.bins):
      print('Bin ({}%) {}: {}'.format(x.utilization, i,[i.name for i in x.get_items()]))

  print('----------------------------------')
  packer._items.append(Item('Z{}'.format(i),2))
  j += 1
  time.sleep(3)

output:
    Bin (100.0%) 0: ['H', 'C', 'F', 'A']
    Bin (100.0%) 1: ['I', 'D']
    Bin (90.91%) 2: ['B', 'E']
    Bin (63.64%) 3: ['G']
    ----------------------------------
    Bin (100.0%) 0: ['H', 'C', 'F', 'A']
    Bin (100.0%) 1: ['I', 'D']
    Bin (90.91%) 2: ['B', 'E']
    Bin (81.82%) 3: ['Z0', 'G']
    ----------------------------------
    Bin (100.0%) 0: ['H', 'C', 'F', 'A']
    Bin (100.0%) 1: ['I', 'D']
    Bin (90.91%) 2: ['B', 'E']
    Bin (100.0%) 3: ['Z0', 'G', 'Z1']
    ----------------------------------
    Bin (100.0%) 0: ['H', 'C', 'F', 'A']
    Bin (100.0%) 1: ['I', 'D']
    Bin (90.91%) 2: ['B', 'E']
    Bin (100.0%) 3: ['Z0', 'G', 'Z1']
    Bin (18.18%) 4: ['Z2']
    ----------------------------------
    Bin (100.0%) 0: ['H', 'C', 'F', 'A']
    Bin (100.0%) 1: ['I', 'D']
    Bin (90.91%) 2: ['B', 'E']
    Bin (100.0%) 3: ['Z0', 'G', 'Z1']
    Bin (36.36%) 4: ['Z2', 'Z3']
    ----------------------------------
    Bin (100.0%) 0: ['H', 'C', 'F', 'A']
    Bin (100.0%) 1: ['I', 'D']
    Bin (90.91%) 2: ['B', 'E']
    Bin (100.0%) 3: ['Z0', 'G', 'Z1']
    Bin (54.55%) 4: ['Z2', 'Z3', 'Z4']

• Note that (xxx%) is the percentage of fullness

Contributors

• Paulo Kuong (@pkuong)