# coding: utf-8

# In[ ]:

# specifying the knapsack instance

from __future__ import division
import numpy as np
import os
import time

numOfItems = 10
instanceNumber = 3
# change path to your needs:
filename = 'C://users/dimo/desktop/teaching/Saclay2015/introToOptimization/02-dynProgAndBranchBound/knapsackinstances/KP-random-%ditems-%d.txt' % (numOfItems, instanceNumber)
w = []
p = []
with open(filename, "r") as text_file:
        for line in text_file:
            ll = line.split()
            if 'W' in ll[0]:
                W = int(ll[2])
            if 'n' not in ll[0] and 'W' not in ll[0]:
                w.append(int(ll[0]))
                p.append(int(ll[1]))

# and its objective and constraint functions:
def f(x):   # objective function
    return np.sum(p*x)

def g(x):   # constraint violation function
    return np.sum(w*x) - W