(完整版)Matlab各种随机数设置.pdf

Matlab 各种随机数设置

randn（伪随机正态分布数）

Normally distributed pseudorandom numbers

Syntax

r = randn(n)

randn(m,n)

randn([m,n])

randn(m,n,p,...)

randn([m,n,p,...])

randn([m,n,p,...]) returns an m-by-n-by-p-by-... array. randn returns a scalar. randn(size(A))

returns an array the same size as A.

r = randn(..., 'double') or r = randn(..., 'single') returns an array of normal values of the specified

class.

Note The size inputs m, n, p, ... should be nonnegative integers. Negative integers are treated

as 0.

The sequence of numbers produced by randn is determined by the internal state of the

uniform pseudorandom number generator that underlies rand, randi, and randn. randn uses one

or more uniform values from that default stream to generate each normal value. Control the

default stream using its properties and methods.

Generate values from a bivariate normal distribution with specified mean vector and

covariance matrix.

mu = [1 2];

Sigma = [1 .5; .5 2]; R = chol(Sigma);

z = repmat(mu,100,1) + randn(100,2)*R;

Replace the default stream at MATLAB startup, using a stream whose seed is based on clock,

so that randn will return different values in different MATLAB sessions. It is usually not desirable

to do this more than once per MATLAB session.

RandStream.setDefaultStream ...