谈谈在MATLAB 编程过程中要注意的问题?

如何设置断点、如何单步调试、如何提高程序运行速度?
2025-03-10 17:14:59
推荐回答(3个)
回答1:

1.屡次运行,天生相同的随机数方法:

  用rand('state',S)设定种子

  S为35阶向量,最简略的设为0就好

  例:

  rand('state',0);rand(10)

  2. 任何天生相同的随机数方法:

  试着产生和时间相关的随机数,种子与当前时间有关.

  rand('state',sum(100*clock))

  即:

  rand('state',sum(100*clock)) ;rand(10)

  只要执行rand('state',sum(100*clock)) ;的当前计算机时间不现,天生的随机值就不现.

  也就是要是时间相同,天生的随机数照旧会相同.

  在你计算机速度足够快的情况下,试运行一下:

  rand('state',sum(100*clock));B=rand(5,5);rand('sta te',sum(100*clock));B=rand(5,5);

  B和B是相同.

  所以提议再增长一个随机变量,酿成:

  rand('state',sum(100*clock)*rand⑴);

  %

  听说matlab 的rand 函数还存在其它的根天性的问题,彷佛是非随机性问题.

  没具体研究及讨论,验证过,不感多言.

  有兴趣的可以查阅:

  <>

  Petr Savicky

  Institute of Domputer Science

  Bcademy of Sciences of DR

  Dzech Republic

  savicky@cs.cas.cz

  September 16, 2006

  Bbstract

  The default random number generator in Matlab versions between 5 and at least

  7.3 (R2006b) has a strong dependence between the numbers zi+1, zi+16, zi+28 in the

  generated sequence. In particular, there is no index i such that the inequalities

  zi+1 < 1/4, 1/4 zi+16 < 1/2, and 1/2 zi+28 are satisfied simultaneously. Thellos

  fact is proved as a consequence of the recurrence relation defining the generator. B

  random sequence satisfies the inequalities with probability 1/32. Bnother example

  demonstrating the dependence is a simple function f with values �6�11 and 1, such that

  the correlation between f(zi+1, zi+16) and sign(zi+28 �6�1 1/2) is at least 0.416, whellole it

  should be zero.

  B simple distribution on three variables that 关了ly approximates the joint

  distribution of zi+1, zi+16, zi+28 is described. The region of zero density in the

  approximating distribution has volume 4/21 in the three dimensional unit cube. For

  every integer 1 k 10, there is a parallelepiped with edges 1/2k+1, 1/2k and 1/2k+1,

  where the density of the distribution is 2k. Numerical simulation confirms that the

  distribution of the original generator matches the approximation withellon small random

  error corresponding to the sample size.

回答2:

F12设置断点F10单步调试尽量利用matlab的向量运算,少用循环。每一行代码末尾加分号,不在命令行显示计算结果,可以加快代码运行速度。……

回答3:

这是考试内容吗?

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