﻿功能:快速求阶乘

格式:BgFactorialFast(f,n)、BgFactorialFast(f)

f:为操作的大数对象,其为指定的数据或者符号变量,注意,其值必须介于0与1E10之间
n:精确的位数,n越大,数据的有效位越多.这里实际精确的位数为n*9位数据.这里的n默认为30.

函数成功返回f的阶乘

例子:

BgFactorialFast(345)//执行命令后得到如下结果，即345!
ans =
"24215638650792346558700053691985855570120556040258652734839783267039961720178323593174739047913617079695531502689473012213820889134885853992818438056445080201482863675240494802269823110125881000284687377104376400792200165127855908498047507347955446603093964326872608000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"