功能: 返回唯一数据(数据去重)

格式: 
DataUnique(a)
DataUnique(a, p)

a : 为待统计的矩阵变量
p : 数值,容错误差,默认1e-15 

说明:
1. 函数执行成功,返回a里唯一的数值

例子:
a =
[ 6.00000000000000    7.50000000000000    1.50000000000000    13.5000000000000
  13.5000000000000    9.00000000000000    9.00000000000000    1.50000000000000
  1.50000000000000    15.0000000000000    3.00000000000000    1.50000000000000
  9.00000000000000    6.00000000000000    6.00000000000000    7.50000000000000 ]
v = DataUnique(a)//回车得到如下结果
v =
[ 1.50000000000000
  3.00000000000000
  6.00000000000000
  7.50000000000000
  9.00000000000000
  13.5000000000000
  15.0000000000000 ]