Gurobi Error for bigger Models: Failed to create model (Java)

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Tobias Buchegger

2022年05月26日 19:15

• 
• 

Hello.

I have an Error when i try to run my program for bigger Models.
n<=4 ... it is working
n>4 ... it is not working

 

Error:
Exception in thread "main" gurobi.GRBException: Failed to create model
    at gurobi.GRBModel.<init>(GRBModel.java:68)
    at Chess_queenproblem.branchAndBound(Chess_queenproblem.java:82)
    at Chess_queenproblem.branchAndBound(Chess_queenproblem.java:192)
    ..... [it is recursive so i have for each new tray the same error] ...
    at Chess_queenproblem.main(Chess_queenproblem.java:53)
Warning: Failed to open log file 'LP.log'

Part of program:
public static void main(String[] arg) throws GRBException
    {     
        //Parameter values
        int n = 5;
        private static Double[][][][] threatedFields = ....;
        private static Boolean[][] fixedFields = ....;
        //Start Groubi
        env = new GRBEnv(true);
        env.set("logFile", "LP.log");
        env.set("OutputFlag", "0");
        env.start();//Start Branch and Bound
       //Start Branch and Bound
        solution  = branchAndBound(threatedFields, fixedFields,n); == Line 53
        env.dispose();

private static boolean[][] branchAndBound(Double[][][][] threatedFields, Boolean[][] fixedFields, int n) throws GRBException
    {
        GRBModel model = new GRBModel(env);
        GRBVar[][] x = new GRBVar[n][n]; == Line 83
        ... do optimization ...
        boolean[][] solutionTrue = branchAndBound(threatedFields, fixedFieldsEnlargedTrue, n); == Line 192
                        

Log:

Gurobi 9.5.1 (win64, Java) logging started Thu May 26 20:36:04 2022 >>> not working n=5 
Gurobi 9.5.1 (win64, Java) logging started Thu May 26 20:36:04 2022 >>> working n=4
        Set parameter LogFile to value "LP.log"

0

• 正式なコメント

  

  Simranjit Kaur

  • Gurobi Staff

  2025年11月16日 23:36

  This post is more than three years old. Some information may not be up to date. For current information, please check the Gurobi Documentation or Knowledge Base. If you need more help, please create a new post in the community forum, or try Gurobot, our chatbot interface offering instant, expert-level support.
• 

  Jaromił Najman

  • Gurobi Staff

  2022年05月30日 08:27

  Did you check whether your program does run out of memory? This is often the case for recursive Java programs which require many objects of significant size, cf. StackOverflowError Vs OurOfMemoryError in Java.

  Did you try re-writing your program in a sequential way to avoid recursion?

  Best regards, 
  Jaromił

  0

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