Commit aaaa0e43 authored by Iustin Pop's avatar Iustin Pop
Browse files

Change the balancing algorithm

This patch changes the balancing algorithm to not iterate linearly over
the instances (in a random, but fixed order), instead selecting at each
step the best next move. This should allow a better score (most of the
time), and usually also a shorter solution.
parent dd4c56ed
......@@ -394,29 +394,43 @@ checkMove :: Table -- ^ The current solution
-> [Instance.Instance] -- ^ List of instances still to move
-> Table -- ^ The new solution
checkMove ini_tbl victims =
let target = head victims
opdx = Instance.pnode target
osdx = Instance.snode target
vtail = tail victims
have_tail = (length vtail) > 0
Table ini_nl _ _ _ = ini_tbl
nodes = filter (\node -> let idx = Node.idx node
in idx /= opdx && idx /= osdx)
$ Container.elems ini_nl
aft_failover = checkSingleStep ini_tbl target ini_tbl Failover
next_tbl =
foldl'
(\ accu_p new_node ->
let
new_idx = Node.idx new_node
pmoves = [ReplacePrimary new_idx,
ReplaceSecondary new_idx]
in
foldl' (checkSingleStep ini_tbl target) accu_p pmoves
) aft_failover nodes
in if have_tail then checkMove next_tbl vtail
else next_tbl
let Table ini_nl _ _ ini_plc = ini_tbl
best_tbl =
foldl -- iterate over all instances, computing the best move
(\ step_tbl target ->
let
opdx = Instance.pnode target
osdx = Instance.snode target
nodes = filter (\node -> let idx = Node.idx node
in idx /= opdx && idx /= osdx)
$ Container.elems ini_nl
aft_failover = checkSingleStep ini_tbl
target ini_tbl Failover
next_tbl = -- iterate over the possible nodes for
-- this instance
foldl'
(\ accu_p new_node ->
let
new_idx = Node.idx new_node
pmoves = [ReplacePrimary new_idx,
ReplaceSecondary new_idx]
in
foldl' -- while doing both possible moves
(checkSingleStep ini_tbl target) accu_p pmoves
) aft_failover nodes
in
compareTables step_tbl next_tbl
) ini_tbl victims
in let
Table _ _ _ best_plc = best_tbl
(target, _, _) = head best_plc
vtail = filter (\inst -> Instance.idx inst /= target) victims
in
if length best_plc == length ini_plc then -- no advancement
ini_tbl
else
if null vtail then best_tbl
else checkMove best_tbl vtail
{- | Auxiliary function for solution computation.
......
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