MATLAB: Java Builder – Multithreading issues

Question

Hello!

I built and compiled my first serious Matlab program to Java class using the Java Builder. I wrote Java driver, which converts the necessary data types from Java to Matlab.

But now I have a problem – I try to use the same class in two parallel threads in my Java application and keep getting exceptions. When I run only one thread it works fine. What can be the problem? Please help me…

Update:

My intention is to use a Random Forest Ensemble, trained previously in Matlab, in a Java application. My Matlab function, which I compiled, using deploytool is:

   function [Probability]=PredictingTest (Predictor)
     load (['D:/Test/Tree.mat'], 'Tree')
     [~, prob]=predict(Tree , Predictor);
     Probability=prob(:,1);
   end
Where:

Predictor input is an integer between -10 to 10. Probability output is a double between 0 to 1. Tree is a .mat file with a CompactTreeBagger object stored in it. Next I deploy the jar files to my Eclipse project, and try to run this Java code:

/* Necessary package imports */
import com.mathworks.toolbox.javabuilder.*;
import PredictTest.*;
public class predict_test {
  
   static MWNumericArray rhs = null;   /* Stores input value */
   static PredictTest prediction;
   static Object[] result = null;    /* Stores the result */
  
   public static void main(String[] args) {
  
  try {
       prediction = new PredictTest();
       rhs=new MWNumericArray(5,MWClassID.DOUBLE);      
       result=prediction.PredictingTest(1, rhs);
       }
      catch (MWException e) {
      e.printStackTrace();
  }}}

Segmentation violation detected at Fri Jul 08 12:02:26 2011:

Configuration:

MATLAB Version: 7.11.0.584 (R2010b)

Processor ID: x86 Family 6 Model 14 Stepping 5, GenuineIntel

Virtual Machine: Java 1.6.0_22-b04 with Sun Microsystems Inc. Java HotSpot™ Client VM mixed mode

Answer 1

Hi,

which version of MATLAB are you using? And could you post both the exception you are seeing and how you call your class?

Titus