Solving linear eqn by efficient-java-matrix-library

Question

I am using the following library for solving linear equation . The link of that library is as follows : efficient-java-matrix-library

I have downloaded the library file and imported in the eclipse . Then I have written the following code to solve a set of linear equations .

 SimpleMatrix A1 = new SimpleMatrix(m,n);
      SimpleMatrix b1 = new SimpleMatrix(m,1);

      for(int i=0;i<m;i++)
      {
          for(int j=0;j<n;j++)
          {
              A1.setRow(i, i, A2[i][j]);
             // System.out.println();
          }
           b1.setColumn(i, 0, B2[i]); 
      }
      try {
          SimpleMatrix x1 = A1.solve(b1);
          for(int i=0;i<x1.getNumElements();i++)
          {
              double value = x1.get(i, 0);
              System.out.println(" value of x"+i+" is "+value);
          }
      } 
      catch ( SingularMatrixException e ) 
      {
        //  throw new IllegalArgument("Singular matrix");
      }

But for this code I am having the following exception .

Exception in thread "main" java.lang.IllegalArgumentException: Specified element is out of bounds: (0 , 1)
    at org.ejml.data.DenseMatrix64F.set(Unknown Source)
    at org.ejml.simple.SimpleBase.setColumn(Unknown Source)
    at com.temp.temp.Main_function.main(Main_function.java:37)

I cant understand why I am getting this error . Can you please help me to solve this error ?

Answer 1

SimpleMatrix A1 = new SimpleMatrix(m,n); SimpleMatrix b1 = new SimpleMatrix(m,1);

  for(int i=0;i<m;i++)
  {
      for(int j=0;j<n;j++)
      {
          A1.setRow(i, j, A2[i][j]);
          double value1 = A1.get(i,j);
          System.out.print(" "+value1);
          // System.out.println();
      }
      b1.setRow(i,0, B2[i]); 
      double value2 = b1.get(i,0);
      System.out.print(" = "+value2);
      System.out.println();
  }


  try {
      SimpleMatrix x1 = A1.solve(b1);
      for(int i=0;i<x1.getNumElements();i++)
      {
          double value = x1.get(i, 0);
          System.out.println(" value of x"+i+" is "+value);
      } 
  } 
  catch ( SingularMatrixException e ) 
  {
    //  throw new IllegalArgument("Singular matrix");
  }