生成给定分布律的随机数

％ r=specrnd(x,p)返回一个来自分布律P(x)=p的随机数

％ r=specrnd(x,p,m,n)返回m*n随机数矩阵

％ p的默认值为等概率-Generate a given distribution law of random number r = specrnd (x, p) returns a from the distribution law P (x) = p of the random number r = specrnd (x, p, m, n) return m* n random Matrix p, such as the default value for the probability