[Cops] Setting physical memory limit

[Yan Xu]

Khoa,

nodeLimit is to specify how many nodes can ALPS process. When reaching this number, ALPS will terminate and return node limit solution status.

The checkMemory parameter is to report how many memory used by ALPS, I only test it for serial code on Linux machine.

Since difference platform has different way to get memory info, ALPS doesn't check memory usage to switch strategy.

For large instance, I guess you can try set ALPS_searchStrategy to depth-first.  Also, try come up a method that tends to generate fewer nodes (like strong branching in solving MILPs).

Hope it helps.

Best,
Yan



-----Original Message-----
From: Khoa Vo [mailto:khoa.vo at informatik.uni-heidelberg.de]
Sent: Friday, February 08, 2008 9:47 AM
To: Yan Xu
Cc: cops at list.coin-or.org
Subject: Setting physical memory limit

Hi Yan,

My ALPS-based program is having problem with memory limitation. In our
cluster, each node (quad-cores processor) has a limitation of 8GB RAM.
One of our testing instances has caused a crash, as the memory it takes
on one node exceeds 8GB.

Is there any parameter in ALPS that I can set a limit of memory? That
means if the total physical memory used in one process exceeds a certain
limit, children ALPS nodes will not be generated anymore? I noticed the
two following parameters, but no number for the memory.

/** The max number of nodes can be processed.
112           Default: ALPS_INT_MAX */
113       nodeLimit,

/** Check memory.
43           Default: false */
44       checkMemory,

Thanks,
Khoa

==================My parameter files=======================
Alps_instance ../data/Harwell-Boeing_small/lns__131.mtx.rnd

Bw_labelingDirection 0

Bw_upperBound 19

Bw_lowerBound 1

Alps_solLimit 1

#Alps_nodeLimit 5000000

Alps_logFileLevel 0

Alps_msgLevel 1
Alps_hubMsgLevel 0
Alps_workerMsgLevel 0

Alps_hubNum 8

Alps_interClusterBalance 1      # 1: balancing load, 0: don't.
Alps_intraClusterBalance 1      # 1: balancing load, 0: don't.

#Alps_searchStrategy 0 # 0: Best, 1: Best-est, 2: Breath, 3: Depth, 4
hybrid
#Alps_searchStrategyRampUp  0

#Alps_staticBalanceScheme 0

#Alps_nodeLogInterval 1000
#Alps_hubWorkClusterSizeLimit 1

Alps_masterInitNodeNum 2000 #3000
Alps_hubInitNodeNum 300 #5000
Alps_unitWorkNodes 10

#Alps_hubWorkClusterSizeLimit 3

#Alps_needWorkThreshold 0.5
#Alps_changeWorkThreshold 0.10

#Alps_donorThreshold 0.3
#Alps_receiverThreshold 0.3

#Alps_masterBalancePeriod 60 #0.3
#Alps_hubReportPeriod 30 #0.5