apps/pci/optimizers/solver/optimizer.py

   1 # -------------------------------------------------------------------------
   2 #   Copyright (c) 2018 AT&T Intellectual Property
   3 #
   4 #   Licensed under the Apache License, Version 2.0 (the "License");
   5 #   you may not use this file except in compliance with the License.
   6 #   You may obtain a copy of the License at
   7 #
   8 #       http://www.apache.org/licenses/LICENSE-2.0
   9 #
  10 #   Unless required by applicable law or agreed to in writing, software
  11 #   distributed under the License is distributed on an "AS IS" BASIS,
  12 #   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13 #   See the License for the specific language governing permissions and
  14 #   limitations under the License.
  15 #
  16 # -------------------------------------------------------------------------
  17 #
  18
  19 import itertools
  20 import os
  21 from collections import defaultdict
  22 import pymzn
  23
  24 from .pci_utils import get_id,mapping
  25
  26 BASE_DIR = os.path.dirname(__file__)
  27 cell_id_mapping = dict()
  28 id_cell_mapping = dict()
  29
  30 def pci_optimize(network_cell_info, cell_info_list, request_json):
  31     global cell_id_mapping, id_cell_mapping
  32     cell_id_mapping, id_cell_mapping = mapping(network_cell_info)
  33     original_pcis = get_original_pci_list(network_cell_info)
  34     unchangeable_pcis = get_ids_of_fixed_pci_cells(request_json['cellInfo'].get('fixedPCICells', []))
  35     neighbor_edges = get_neighbor_list(network_cell_info)
  36     second_level_edges = get_second_level_neighbor(network_cell_info)
  37     ignorable_links = get_ignorable_links(network_cell_info, request_json)
  38     anr_flag = is_anr(request_json)
  39
  40     dzn_data = build_dzn_data(cell_info_list, ignorable_links, neighbor_edges, second_level_edges, anr_flag, original_pcis, unchangeable_pcis)
  41
  42     return build_pci_solution(dzn_data, ignorable_links, anr_flag)
  43
  44 def get_ids_of_fixed_pci_cells(fixed_pci_list):
  45     fixed_pci_ids = set()
  46     for cell in fixed_pci_list:
  47         fixed_pci_ids.add(cell_id_mapping[cell])
  48     return fixed_pci_ids
  49
  50
  51 def get_cell_id_pci_mapping(network_cell_info):
  52     original_pcis = dict()
  53     for cell in network_cell_info['cell_list']:
  54         for nbr in cell['nbr_list']:
  55             if cell_id_mapping[nbr['targetCellId']] not in original_pcis:
  56                 original_pcis[cell_id_mapping[nbr['targetCellId']]] = nbr['pciValue']
  57     return original_pcis
  58
  59
  60 def get_original_pci_list(network_cell_info):
  61     cell_id_pci_mapping = get_cell_id_pci_mapping(network_cell_info)
  62     original_pcis_list = []
  63     for i in range(len(cell_id_pci_mapping)):
  64         original_pcis_list.append(cell_id_pci_mapping.get(i))
  65     return original_pcis_list
  66
  67
  68 def build_pci_solution(dzn_data, ignorable_links, anr_flag):
  69     mzn_solution = solve(get_mzn_model(anr_flag), dzn_data)
  70     if mzn_solution == 'UNSATISFIABLE':
  71         return mzn_solution
  72     solution = {'pci': mzn_solution[0]['pci']}
  73
  74     if anr_flag:
  75         removables = defaultdict(list)
  76         used_ignorables = mzn_solution[0]['used_ignorables']
  77         index = 0
  78         for i in ignorable_links:
  79             if used_ignorables[index] > 0:
  80                 removables[i[0]].append(i[1])
  81             index += 1
  82         solution['removables'] = removables
  83     return solution
  84
  85
  86 def build_dzn_data(cell_info_list, ignorable_links, neighbor_edges, second_level_edges, anr_flag,original_pcis, unchangeable_pcis):
  87     dzn_data = {
  88         'NUM_NODES': len(cell_info_list),
  89         'NUM_PCIS': len(cell_info_list),
  90         'NUM_NEIGHBORS': len(neighbor_edges),
  91         'NEIGHBORS': get_list(neighbor_edges),
  92         'NUM_SECOND_LEVEL_NEIGHBORS': len(second_level_edges),
  93         'SECOND_LEVEL_NEIGHBORS': get_list(second_level_edges),
  94         'PCI_UNCHANGEABLE_CELLS': unchangeable_pcis,
  95         'ORIGINAL_PCIS': original_pcis
  96     }
  97     if anr_flag:
  98         dzn_data['NUM_IGNORABLE_NEIGHBOR_LINKS'] = len(ignorable_links)
  99         dzn_data['IGNORABLE_NEIGHBOR_LINKS'] = get_list(ignorable_links)
 100     return dzn_data
 101
 102
 103 def get_mzn_model(anr_flag):
 104     if anr_flag:
 105         mzn_model = os.path.join(BASE_DIR, 'min_confusion_inl.mzn')
 106     else:
 107         mzn_model = os.path.join(BASE_DIR, 'no_conflicts_no_confusion.mzn')
 108     return mzn_model
 109
 110
 111 def is_anr(request_json):
 112     return 'pci-anr' in request_json["requestInfo"]["optimizers"]
 113
 114
 115 def get_list(edge_list):
 116     array_list = []
 117     for s in edge_list:
 118         array_list.append([s[0], s[1]])
 119     return sorted(array_list)
 120
 121
 122 def solve(mzn_model, dzn_data):
 123     return pymzn.minizinc(mzn=mzn_model, data=dzn_data)
 124
 125
 126 def get_neighbor_list(network_cell_info):
 127     neighbor_list = set()
 128     for cell in network_cell_info['cell_list']:
 129         add_to_neighbor_list(network_cell_info, cell, neighbor_list)
 130     return neighbor_list
 131
 132
 133 def add_to_neighbor_list(network_cell_info, cell, neighbor_list):
 134     for nbr in cell.get('nbr_list', []):
 135         host_id = cell['id']
 136         nbr_id = get_id(network_cell_info, nbr['targetCellId'])
 137         if nbr_id and host_id != nbr_id:
 138             neighbor_list.add((host_id, nbr_id))
 139
 140
 141 def get_second_level_neighbor(network_cell_info):
 142     second_neighbor_list = set()
 143     for cell in network_cell_info['cell_list']:
 144         comb_list = build_second_level_list(network_cell_info, cell)
 145         for comb in comb_list:
 146             if comb[0] and comb[1]:
 147                 second_neighbor_list.add((comb[0], comb[1]))
 148     return sorted(second_neighbor_list)
 149
 150
 151 def build_second_level_list(network_cell_info, cell):
 152     second_nbr_list = []
 153     for nbr in cell.get('nbr_list', []):
 154         second_nbr_list.append(get_id(network_cell_info, nbr['targetCellId']))
 155     return [list(elem) for elem in list(itertools.combinations(second_nbr_list, 2))]
 156
 157
 158 def get_ignorable_links(network_cell_info, request_json):
 159     ignorable_list = set()
 160     anr_input_list = request_json["cellInfo"].get('anrInputList', [])
 161     if anr_input_list:
 162         for anr_info in anr_input_list:
 163             cell_id = get_id(network_cell_info, anr_info['cellId'])
 164             anr_removable = anr_info.get('removeableNeighbors', [])
 165             for anr in anr_removable:
 166                 ignorable_list.add((cell_id, get_id(network_cell_info, anr)))
 167     return ignorable_list