code: public void eachInRow(int i, VectorProcedure procedure) {
          VectorIterator it = iteratorOfRow(i);
  
          while (it.hasNext()) {
              double x = it.next();
              int j = it.index();
              procedure.apply(j, x);
          }
      }
docs: Applies given {@code procedure} to each element of specified row of this matrix.
  
  @param i the row index
  @param procedure the vector procedure