code: public void setColumn(int j, double value) {
          VectorIterator it = iteratorOfColumn(j);
  
          while (it.hasNext()) {
              it.next();
              it.set(value);
          }
      }
docs: <p>
  Sets all elements of the specified column of this matrix to given {@code value}.
  </p>
  
  @param j the column index
  @param value the element's new value