code: @Override
      public boolean isSingular() {
  
          for( int i = 0; i < m; i++ ) {
              double real = dataLU[i*stride+i*2];
              double imaginary = dataLU[i*stride+i*2+1];
  
              double mag2 = real*real + imaginary*imaginary;
  
              if( mag2 < UtilEjml.EPS*UtilEjml.EPS )
                  return true;
          }
          return false;
      }
docs: Determines if the decomposed matrix is singular.  This function can return
  false and the matrix be almost singular, which is still bad.
  
  @return true if singular false otherwise.