大家好，我在看一段代码的时间运行不出来，显示错误如下：
Error: unknownValueForOption: Unknown value 0 for optbase optionunknownValueForOption: Unknown value 0 for optbase optionunknownValueForOption: Unknown value 2 for optbase optionunknownValueForOption: Unknown value 0 for optbase optionunknownValueForOption: Unknown value 2 for optbase optionunknownValueForOption: Unknown value 0 for optbase option
In addition: Warning message:
In if (is(value) != "optimbase") { :
  the condition has length > 1 and only the first element will be used

没有用过这种算法，不知道怎么回事，麻烦高人解释下.
这段代码来自于A First Course in Statistical Programming with R （2nd Edition）的7.3节最后一部分。
谢谢！