ls dyna计算时内存不够该如何解决？？

 *** Error 70021 (OTH+21)

     Memory is set 51336845 words short

     memory size 800000000

     Increase the memory size by one of the following

     where #### is the number of words requested:

       1) On the command line set - memory=####

       2) In the input file define memory with *KEYWORD

       i.e., *KEYWORD #### or *KEYWORD memory=####

显示这样的错误