# Copyright 2011 Hakan Kjellerstrand hakank@bonetmail.com
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

"""

  Blending problem in Google or-tools.

  From the OPL model blending.mod.

  This model was created by Hakan Kjellerstrand (hakank@bonetmail.com)
  Also see my other Google CP Solver models: http://www.hakank.org/google_or_tools/
"""
import sys
from linear_solver import pywraplp


def main(sol = 'GLPK'):

  # Create the solver.

  print 'Solver: ', sol

  # using GLPK
  if sol == 'GLPK':
    solver = pywraplp.Solver('CoinsGridGLPK',
                             pywraplp.Solver.GLPK_MIXED_INTEGER_PROGRAMMING)
  else:
  # Using CLP
      solver = pywraplp.Solver('CoinsGridCLP',
                               pywraplp.Solver.CBC_MIXED_INTEGER_PROGRAMMING)


  #
  # data
  #
  NbMetals = 3
  NbRaw = 2
  NbScrap = 2
  NbIngo = 1
  Metals = range(NbMetals)
  Raws = range(NbRaw)
  Scraps = range(NbScrap)
  Ingos = range(NbIngo)

  CostMetal = [22, 10, 13]
  CostRaw =  [6, 5]
  CostScrap =  [ 7, 8]
  CostIngo =   [9 ]
  Low =  [0.05, 0.30, 0.60]
  Up =  [0.10, 0.40, 0.80]
  PercRaw = [ [ 0.20, 0.01 ], [ 0.05, 0 ], [ 0.05, 0.30 ] ]
  PercScrap =  [ [ 0 , 0.01 ], [ 0.60, 0 ], [ 0.40, 0.70 ] ]
  PercIngo =  [ [ 0.10 ], [ 0.45 ], [ 0.45 ] ]
  Alloy  = 71

  #
  # variables
  #
  p = [solver.NumVar(0, solver.Infinity(), 'p[%i]' % i) for i in Metals]
  r = [solver.NumVar(0, solver.Infinity(), 'r[%i]' % i) for i in Raws]
  s = [solver.NumVar(0, solver.Infinity(), 's[%i]' % i) for i in Scraps]
  ii = [solver.IntVar(0, solver.Infinity(), 'ii[%i]' % i) for i in Ingos]
  metal = [solver.NumVar(Low[j]*Alloy,  Up[j]*Alloy, 'metal[%i]' % j)
           for j in Metals]

  z = solver.NumVar(0, solver.Infinity(), 'z')

  #
  # constraints
  #

  solver.Add(z ==
             solver.Sum([CostMetal[i] * p[i]  for i in Metals]) +
             solver.Sum([CostRaw[i]   * r[i]  for i in Raws]) +
             solver.Sum([CostScrap[i] * s[i]  for i in Scraps]) +
             solver.Sum([CostIngo[i]  * ii[i] for i in Ingos]))


  for j in Metals:
    solver.Add(
      metal[j] == p[j] +
      solver.Sum([PercRaw[j][k]   * r[k]  for k in Raws]) +
      solver.Sum([PercScrap[j][k] * s[k]  for k in Scraps]) +
      solver.Sum([PercIngo[j][k]  * ii[k] for k in Ingos]))


  solver.Add(solver.Sum(metal) == Alloy)

  objective = solver.Minimize(z)

  #
  # solution and search
  #
  solver.Solve()

  print

  print 'z = ', solver.ObjectiveValue()
  print 'Metals'
  for i in Metals:
    print p[i].SolutionValue(),
  print

  print 'Raws'
  for i in Raws:
    print r[i].SolutionValue(),
  print

  print 'Scraps'
  for i in Scraps:
    print s[i].SolutionValue(),
  print

  print 'Ingos'
  for i in Ingos:
    print ii[i].SolutionValue(),
  print

  print 'Metals'
  for i in Metals:
    print metal[i].SolutionValue(),
  print

  print

  print 'walltime  :', solver.WallTime(), 'ms'
  if sol == 'CBC':
    print 'iterations:', solver.Iterations()


if __name__ == '__main__':
    sol = 'GLPK'

    if len(sys.argv) > 1:
      sol = sys.argv[1]
      if sol != 'GLPK' and sol != 'CBC':
        print 'Solver must be either GLPK or CBC'
        sys.exit(1)

    main(sol)