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||matlab 中 rand 函数是产生0到1的随机分布
1>、RAND:Uniformly distributed random numbers.
标准化分布的随机数
2>、RAND(N) is an N-by-N matrix with random entries, chosen from a uniform distribution on the interval (0.0,1.0).
rand(N)为随机生成一个在【0,1】之间的n维随机矩阵。
3>、RAND(M,N) and RAND([M,N]) are M-by-N matrices with random entries.
rand(M,N) and rand([M,N])随机生成一个在【0,1】之间的m,n维随机矩阵。
4>、RAND(M,N,P,…) or RAND([M,N,P,…]) generate random arrays.
rand(M,N,P) and rand([M,N])随机生成 P 个在【0,1】之间的m,n维随机矩阵。 5>、RAND with no arguments is a scalar whose value changes each time itis referenced. RAND(SIZE(A)) is the same size as A. 没有参数的rand是一个标量,它的值在每次被引用时都改变。rand( size(A) )是与 A 具有相同尺寸。6>、RAND produces pseudo-random numbers.The sequence of numbersgenerated is determined by the state of the generator.Since MATLABresets the state at start-up, the sequence of numbers generated willbe the same unless the state is changed.
rand 产生伪随机数。生成的序列数由生成器的状态决定。由于 MATLAB 启动时重置状态,生成的序列数都是一样的除非状态改变。
7>、S = RAND(‘state’) is a 35-element vector containing the current stateof the uniform generator.RAND(‘state’,S) resets the state to S. 8>、RAND(‘state’,0) resets the generator to its initial state.
重新恢复初始状态,刚运行matlab时候的状态
9>、RAND(‘state’,J), for integer J, resets the generator to its J-th state.
安排种子产生第 j 个状态
10>、RAND(‘state’,sum(100*clock)) resets it to a different state each time.
根据时间产生不同的随机数 ~~~~~~~~~~~~~~~~~~~~~~rand above~~~~~~~~~~~~~~~~~~~~~~~~~~
>> x = rand(1,10)
x =
Columns 1 through 6
0.3786 0.8116 0.5328 0.3507 0.9390 0.8759
Columns 7 through 10
0.5502 0.6225 0.5870 0.2077
(2)function2:randn
||matlab中 randn 函数是产生标准正态分布
1>、RANDN产生正态分布数的语法:
标准化分布的随机数 ;
RANDN(N) :产生N× N的矩阵,其元素是按正态分布的数组;
RANDN(M,N) and RANDN([M,N]):产生M×N的矩阵;
RANDN(M,N,P,…) or RANDN([M,N,P…])产生随机序列;
2>、RANDN产生伪随机数的语法:
S = RANDN(‘state’) 是一个二元向量,包括标准发生器的状态;
RANDN(‘state’,S):设置发生器的状态为S(即标准状态);
RANDN(‘state’,0):设置发生器的初始状态;
RANDN(‘state’,J):J为整数,设置发生器到J阶状态;
3>、MATlAB 4.X应用一个单独的种子来产生随机数:
RANDN(‘seed’,0) and RANDN(‘seed’,J)作用与RANDN(‘state’,0)和RANDN(‘state’,J)一样,但使用Matlab 4.x随机数发生器。
RANDN(‘seed’):返回MATlAB 4.X发生器的当前种子。
>> x = randn(1,10)
x =
Columns 1 through 6
-0.1623 -0.1461 -0.5320 1.6821 -0.8757 -0.4838
Columns 7 through 10
-0.7120 -1.1742 -0.1922 -0.2741
(3)function3:randint
matlab 中 randint 是产生整数随机数,默认为 0 和 1
>> x = randi(1,10)
x =
1 1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 1 1
>> x = randint(1,10)
Warning: This is an obsolete function and may be removed in the
future.
Please use RANDI instead.
To disable this warning, type
warning(‘off’,’comm:obsolete:randint’).
x =
1 1 1 0 1 0 1 1 0 0
>> x = RANDI(1,10)
Undefined function ‘RANDI’ for input arguments of type ‘double’.
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