osdf/optimizers/pciopt/solver/optimizer.py

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   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
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   8 #       http://www.apache.org/licenses/LICENSE-2.0
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  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
  23 import pymzn
  24
  25 from .pci_utils import get_id
  26
  27 BASE_DIR = os.path.dirname(__file__)
  28
  29
  30 def pci_optimize(network_cell_info, cell_info_list, request_json):
  31     neighbor_edges = get_neighbor_list(network_cell_info)
  32     second_level_edges = get_second_level_neighbor(network_cell_info)
  33     ignorable_links = get_ignorable_links(network_cell_info, request_json)
  34     anr_flag = is_anr(request_json)
  35
  36     dzn_data = build_dzn_data(cell_info_list, ignorable_links, neighbor_edges, second_level_edges, anr_flag)
  37
  38     return build_pci_solution(dzn_data, ignorable_links, anr_flag)
  39
  40
  41 def build_pci_solution(dzn_data, ignorable_links, anr_flag):
  42     mzn_solution = solve(get_mzn_model(anr_flag), dzn_data)
  43
  44     solution = {'pci': mzn_solution[0]['pci']}
  45
  46     if anr_flag:
  47         removables = defaultdict(list)
  48         used_ignorables = mzn_solution[0]['used_ignorables']
  49         index = 0
  50         for i in ignorable_links:
  51             if used_ignorables[index] > 0:
  52                 removables[i[0]].append(i[1])
  53             index += 1
  54         solution['removables'] = removables
  55     return solution
  56
  57
  58 def build_dzn_data(cell_info_list, ignorable_links, neighbor_edges, second_level_edges, anr_flag):
  59     dzn_data = {
  60         'NUM_NODES': len(cell_info_list),
  61         'NUM_PCIS': len(cell_info_list),
  62         'NUM_NEIGHBORS': len(neighbor_edges),
  63         'NEIGHBORS': get_list(neighbor_edges),
  64         'NUM_SECOND_LEVEL_NEIGHBORS': len(second_level_edges),
  65         'SECOND_LEVEL_NEIGHBORS': get_list(second_level_edges)
  66     }
  67     if anr_flag:
  68         dzn_data['NUM_IGNORABLE_NEIGHBOR_LINKS'] = len(ignorable_links)
  69         dzn_data['IGNORABLE_NEIGHBOR_LINKS'] = get_list(ignorable_links)
  70     return dzn_data
  71
  72
  73 def get_mzn_model(anr_flag):
  74     if anr_flag:
  75         mzn_model = os.path.join(BASE_DIR, 'min_confusion_inl.mzn')
  76     else:
  77         mzn_model = os.path.join(BASE_DIR, 'no_conflicts_no_confusion.mzn')
  78     return mzn_model
  79
  80
  81 def is_anr(request_json):
  82     return 'pci-anr' in request_json["requestInfo"]["optimizers"]
  83
  84
  85 def get_list(edge_list):
  86     array_list = []
  87     for s in edge_list:
  88         array_list.append([s[0], s[1]])
  89     return sorted(array_list)
  90
  91
  92 def solve(mzn_model, dzn_data):
  93     return pymzn.minizinc(mzn=mzn_model, data=dzn_data)
  94
  95
  96 def get_neighbor_list(network_cell_info):
  97     neighbor_list = set()
  98     for cell in network_cell_info['cell_list']:
  99         add_to_neighbor_list(network_cell_info, cell, neighbor_list)
 100     return neighbor_list
 101
 102
 103 def add_to_neighbor_list(network_cell_info, cell, neighbor_list):
 104     for nbr in cell.get('nbr_list', []):
 105         host_id = cell['id']
 106         nbr_id = get_id(network_cell_info, nbr['cellId'])
 107         if nbr_id and host_id != nbr_id:
 108             neighbor_list.add((host_id, nbr_id))
 109
 110
 111 def get_second_level_neighbor(network_cell_info):
 112     second_neighbor_list = set()
 113     for cell in network_cell_info['cell_list']:
 114         comb_list = build_second_level_list(network_cell_info, cell)
 115         for comb in comb_list:
 116             if comb[0] and comb[1]:
 117                 second_neighbor_list.add((comb[0], comb[1]))
 118     return sorted(second_neighbor_list)
 119
 120
 121 def build_second_level_list(network_cell_info, cell):
 122     second_nbr_list = []
 123     for nbr in cell.get('nbr_list', []):
 124         second_nbr_list.append(get_id(network_cell_info, nbr['cellId']))
 125     return [list(elem) for elem in list(itertools.combinations(second_nbr_list, 2))]
 126
 127
 128 def get_ignorable_links(network_cell_info, request_json):
 129     ignorable_list = set()
 130     anr_input_list = request_json["cellInfo"].get('anrInputList', [])
 131     if anr_input_list:
 132         for anr_info in anr_input_list:
 133             cell_id = get_id(network_cell_info, anr_info['cellId'])
 134             anr_removable = anr_info.get('removeableNeighbors', [])
 135             for anr in anr_removable:
 136                 ignorable_list.add((cell_id, get_id(network_cell_info, anr)))
 137     return ignorable_list