code: @Override
      public boolean isSingular() {
          for( int i = 0; i < m; i++ ) {
              if( Math.abs(dataLU[i* n +i]) < 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.