budget.py

#The input data should be in CSV format.
# Each row is a campaign. The columns are (description and variable name):
# Campaign id (id)
# Conversion rate (cvr)
# Bid price (price)
# Max allocated campaign budget (max_allocation)

import csv
import sys

class Campaign(object):
    def __init__(self, row):
        self.id = row['id']
        self.price = float(row['price'])
        self.cvr = float(row['cvr'])
        self.k = str(self.cvr / self.price)
        self.max_allocation = float(row['max_allocation'])
        self.row = row
        self.x = ''.join(['x', self.id])

    def __str__(self):
        return str(self.row)

def main(csvfile, total_budget):
    campaigns = []
    with open(csvfile, 'r') as csvfile:
        input_reader = csv.DictReader(csvfile, delimiter=',')
        for row in input_reader:
            c = Campaign(row)
            campaigns.append(c)
    code = ''
    # add variables section
    for c in campaigns:
        code += ' '.join(['var', c.x])
        code += ';\n'

    # add maximize obj
    code += '\nmaximize obj: '
    linear_parts = []
    for c in campaigns:
        linear_parts.append('*'.join([c.k, c.x]))
    code += '+'.join(linear_parts)
    code += ';\n'

    # add constraint of total budget
    xs = []
    for c in campaigns:
        xs.append(c.x)

    code += 's.t. budget: '
    code += str('+'.join(xs))
    code += ' <= %f;\n' % (total_budget)
    # add constrains on each campaign
    for c in campaigns:
        code += 's.t. campaign_' + c.id + ': ' + '0 <= ' + c.x + " <= " + str(c.max_allocation) + ';\n'

    code += '\nsolve;\n'
    code += 'display ' + ','.join(xs) + ';\n'
    code += 'end;\n'
    print code


if __name__ == "__main__":
    if len(sys.argv) != 3:
        print "Usage: python budget.py input_csv total_budget"
    csvfile = sys.argv[1]
    total_budget = float(sys.argv[2])
    main(csvfile, total_budget)