What 0 represents in rand function?

2014 6 26
1 个回答
回答已采纳
更新时间：2014 7 9
6 次查看（30 天）

0 个投票

What rand ('state', 0) is represents. i read in the document, it shows that it is generating random number. Not clear about what state and 0 represents. how can i verify it in matlab?
Also it is mentioned old version follows this way of representation. In new version it is changed. if so how i can represent it in current version. will current version still accept the above line?

2 个评论
显示 无 隐藏 无

SRI
SRI 2014-6-26
Hi
Did you try typing this command in matlab,since it outperform no result
subha
subha 2014-6-26
编辑：subha 2014-6-26
yes i tried by typing. i got same. thats why to clarify i posted here

请先登录，再进行评论。

请先登录，再回答此问题。

 采纳的回答

Geoff Hayes
Geoff Hayes 2014-6-26

1 个投票

See this link http://www.mathworks.com/help/matlab/math/updating-your-random-number-generator-syntax.html which discusses the "discouraged" syntaxes of rand, which includes your example of rand('state',0).
From the documentation:
In earlier versions of MATLAB®, you controlled the random number generator used by the rand and randn functions with the 'seed', 'state' or 'twister' inputs...These syntaxes referred to different types of generators, and they will be removed in a future release for the following reasons:
  • The terms 'seed' and 'state' are misleading names for the generators.
  • All of the former generators except 'twister' are flawed.
  • They unnecessarily use different generators for rand and randn.
It goes on to discuss what the intent was behind rand('state',sd), why it was discouraged, and what it should be replaced by.
In your case, the alternative for rand('state',sd) would be rng(sd). It is best to use the recommended alternative as per the note.
You can verify that the original call still does work (though it should be replaced!). In the Command Window type
rand('state',0)
A = rand(100,1);
rand('state',0);
B = rand(100,1);
find((A-B)~=0)
Note that A and B will have the same set of randomly generated numbers, so find((A-B)~=0) will be zero.

4 个评论
显示 2更早的评论 隐藏 2更早的评论

subha
subha 2014-7-7
Thanks for your explanation. could you please explain me the difference between rng(0) and rng('shuffle') with some example.
If i use both in one program what will be the effect?
Geoff Hayes
Geoff Hayes 2014-7-7
Please check out the documentation for rng which states
rng(sd) seeds the random number generator using the nonnegative integer sd so that rand, randi, and randn produce a predictable sequence of numbers.
rng('shuffle') seeds the random number generator based on the current time so that rand, randi, and randn produce a different sequence of numbers after each time you call rng.
Alternate between the two and observe what happens when you call (say)
randn(5,1)
between each call to rng.
subha
subha 2014-7-8
When i typed, rng(0)and x= rand(1,5), every time i run, i get same random values. But if i type rng('shuffle') and then x=rand(1,5), it provides different random numbers each time. I understand this from your statement as well as from documents. If i use both, for example rng(0) and rng('shuffle') and then x=rand(1,5), i guess rng('shuffle') overwrites rng(0). it means, i will get different sequence of numbers every time. Am i right?
Geoff Hayes
Geoff Hayes 2014-7-9
Yes. Because you call rng('shuffle') after rng(0) there will be a different sequence of numbers.

请先登录，再进行评论。

更多回答（0 个）

类别

在 帮助中心 和 File Exchange 中查找有关 Creating and Concatenating Matrices 的更多信息

标签

尚未输入任何标签。

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by