Topic
  • 2 replies
  • Latest Post - ‏2012-05-06T22:43:23Z by Maissa
pradeepram80
pradeepram80
23 Posts

Pinned topic CPLEX Out of Memory Error

‏2011-12-05T17:58:27Z |
I'm running a LP and get the CPLEX 1001: Out of memory error. I'm running a model with 1,674,474 variables and 1,014,376 constraints. I've about 3GB of RAM and 2GB of virtual memory. When I look at the Task manager at the time I get this error, there is still 1.3GB of RAM still available and I think this is enough to get a solution. Am I running into any preset memory limits inside CPLEX?

Please see attached printscreen of my task manager.

Thanks in advance
Updated on 2012-05-06T22:43:23Z at 2012-05-06T22:43:23Z by Maissa
  • SystemAdmin
    SystemAdmin
    1883 Posts

    Re: CPLEX Out of Memory Error

    ‏2011-12-07T22:42:12Z  
    You may be running into the architectural limitations of your system. I suspect your machine is a 32 bit system wherein the OS can only provide a maximum of 2Gbs of space to any given application (subject to further limitations). Once the application demands more memory than what the OS can provide it with, the 'out-of-memory' error is thrown.

    With 1.6M variables and 1M constraints, your model is quite large. You could try setting the MemoryEmphasis paramter to true/1 and the NodeFileInd parameter to 3 and see if they help reduce the memory footprint thereby letting you solve the model on the machine. If not, the ultimate solution for large problems is to solve using a 64 bit system wherein you practically have limitless memory (subject to what the RAM can support). The CPLEX Optimization Studio contains some information about how one could deal with such situations at:

    publib.boulder.ibm.com/infocenter/cosinfoc/v12r3/topic/ilog.odms.cplex.help/Content/Optimization/Documentation/Optimization_Studio/_pubskel/ps_usrmancplex1862.html

    Some other tips and tricks can be found in the technote below:

    http://www-01.ibm.com/support/docview.wss?uid=swg21400051

    Hope this helps.
  • Maissa
    Maissa
    6 Posts

    help CPLEX

    ‏2012-05-06T22:43:23Z  
    You may be running into the architectural limitations of your system. I suspect your machine is a 32 bit system wherein the OS can only provide a maximum of 2Gbs of space to any given application (subject to further limitations). Once the application demands more memory than what the OS can provide it with, the 'out-of-memory' error is thrown.

    With 1.6M variables and 1M constraints, your model is quite large. You could try setting the MemoryEmphasis paramter to true/1 and the NodeFileInd parameter to 3 and see if they help reduce the memory footprint thereby letting you solve the model on the machine. If not, the ultimate solution for large problems is to solve using a 64 bit system wherein you practically have limitless memory (subject to what the RAM can support). The CPLEX Optimization Studio contains some information about how one could deal with such situations at:

    publib.boulder.ibm.com/infocenter/cosinfoc/v12r3/topic/ilog.odms.cplex.help/Content/Optimization/Documentation/Optimization_Studio/_pubskel/ps_usrmancplex1862.html

    Some other tips and tricks can be found in the technote below:

    http://www-01.ibm.com/support/docview.wss?uid=swg21400051

    Hope this helps.
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