从系统自带帮助文件可以看出 , CALL RANUNI Routine 对随机数种子和随机数流有更多控制 。
The CALL RANUNI routine, an alternative to the RANUNI function, gives greater control of the seed and random number streams.
If you want to change the seed value during execution, you must use the CALL RANUNI routine instead of the RANUNI function.