From 24c6acc027fc0a8621f8111da418e180fff16b62 Mon Sep 17 00:00:00 2001
From: EstherLerouzic <esther.lerouzic@orange.com>
Date: Mon, 31 Aug 2020 14:04:54 +0200
Subject: [PATCH] Refactor step4 of the compute_path_dsjctn

Previous implementation selected last candidate in case both routing
and disjunction constraints could not be applied. The new implementation
elaborates an alternate list where each feasible paths satisfyng
disjunction constraint but not route constraint is recorded. The algorithm
then preferably selects a feasible path that satisfies all constraints and
if none is found and route constraint is LOOSE, the first set of paths
that satisfy disjunction is selected (instead of the last one).

Signed-off-by: EstherLerouzic <esther.lerouzic@orange.com>
Change-Id: Iba44397d105006a98539494d821cc83dc3e3bbd9
---
 gnpy/topology/request.py | 37 +++++++++++++++++++------------------
 1 file changed, 19 insertions(+), 18 deletions(-)

diff --git a/gnpy/topology/request.py b/gnpy/topology/request.py
index b150c434..3f6db638 100644
--- a/gnpy/topology/request.py
+++ b/gnpy/topology/request.py
@@ -788,33 +788,34 @@ def compute_path_dsjctn(network, equipment, pathreqlist, disjunctions_list):
     # TODO: keep a version without the loose constraint
     for this_d in disjunctions_list:
         temp = []
+        alternatetemp = []
         for j, sol in enumerate(candidates[this_d.disjunction_id]):
             testispartok = True
+            testispartnokloose = True
             for pth in sol:
                 # print(f'test {allpaths[id(pth)].req.request_id}')
                 # print(f'length of route {len(allpaths[id(pth)].req.nodes_list)}')
                 if allpaths[id(pth)].req.nodes_list:
-                    # if pth does not containt the ordered list node, remove sol from the candidate
-                    # except if this was the last solution: then check if the constraint is loose
-                    # or not
+                    # if any pth from sol does not contain the ordered list node,
+                    # remove sol from the candidate, except if constraint was loose:
+                    # then keep sol as an alternate solution
                     if not ispart(allpaths[id(pth)].req.nodes_list, pth):
-                        # print(f'nb of solutions {len(temp)}')
-                        if j < len(candidates[this_d.disjunction_id]) - 1:
-                            msg = f'removing {sol}'
-                            LOGGER.info(msg)
-                            testispartok = False
-                            # break
-                        else:
-                            if 'LOOSE' in allpaths[id(pth)].req.loose_list:
-                                LOGGER.info(f'Could not apply route constraint' +
-                                            f'{allpaths[id(pth)].req.nodes_list} on request' +
-                                            f' {allpaths[id(pth)].req.request_id}')
-                            else:
-                                LOGGER.info(f'removing last solution from candidate paths\n{sol}')
-                                testispartok = False
+                        testispartok = False
+                        if 'STRICT' in allpaths[id(pth)].req.loose_list:
+                            LOGGER.info(f'removing solution from candidate paths\n{pth}')
+                            testispartnokloose = False
+                            break
             if testispartok:
                 temp.append(sol)
-        candidates[this_d.disjunction_id] = temp
+            elif testispartnokloose:
+                LOGGER.info(f'Adding solution as alternate solution not satisfying constraint\n{pth}')
+                alternatetemp.append(sol)
+        if temp:
+            candidates[this_d.disjunction_id] = temp
+        elif alternatetemp:
+            candidates[this_d.disjunction_id] = alternatetemp
+        else:
+            candidates[this_d.disjunction_id] = []
 
     # step 5 select the first combination that works
     pathreslist_disjoint = {}