docs: public static boolean isUpperTriangle(DMatrixRMaj A , int hessenberg , double tol ) {
          for( int i = hessenberg+1; i < A.numRows; i++ ) {
              int maxCol = Math.min(i-hessenberg, A.numCols);
              for( int j = 0; j < maxCol; j++ ) {
                  if( !(Math.abs(A.unsafe_get(i,j)) <= tol) ) {
                      return false;
                  }
              }
          }
          return true;
      }