Dynamic changing values

2 次查看（过去 30 天）
REN
REN 2011-3-8
Hello, I have a question about dynamic changing values.
A list of values (or maybe vectors or maybe matrices): a, b, c, d, e, f, ... ...
There are equations between a, b, c, and d, e, f
---------------
*a* , b, c,
---------------
*d*, e, f ....
---------------
a = x1*b + x2 * c
d = x1*e + x2 * f
values *a* depends on value b and c
values *d* depends on value e and f
x1, x2 are two constant,
And b, c, e, f are variables, their values keep updating in a loop. How to update a, d's values dynamically once b, c, e, f are changed?
I see matlab has no pointer like C, C++. Can matlab do changing values dynamically?
Thanks in advance for your help!

请先登录，再回答此问题。

采纳的回答

Walter Roberson
Walter Roberson 2011-3-8
If you have access to the symbolic toolbox, then you can define your values symbolically, and then when you need a particular numeric value, subs() the current values of the independent variables and double() the result of subs() to get the double precision representation of the resulting symbolic number.
  9 个评论
显示 7更早的评论
Walter Roberson
Walter Roberson 2011-3-8
num2cell(), not mat2cell().
REN
REN 2011-3-9
Yes, thanks again Jiro and Walter for your good idea . I do use mat2cell()(because thess variables are from large matrix) then deal(t{:}) as you suggest.

请先登录，再进行评论。

更多回答（2 个）

Jiro Doke
Jiro Doke 2011-3-8
Just redefine a and d after you update the other values:
for id = 1:100
a = x1*b + x2 * c
d = x1*e + x2 * f
...
<do your stuff>
...
<update b, c, e, f>
end
  3 个评论
显示 1更早的评论
Jiro Doke
Jiro Doke 2011-3-8
Well, I guess I don't fully understand your question. In my above example, every time through the loop, a and d are updated with the new set of values for b, c, e, f. Can you explain why this doesn't work?
REN
REN 2011-3-8
In my case, there are too many variables like a, d.
Writing a long list of varibles in for loop is a bit tedious. Thanks your help anyway...

请先登录，再进行评论。

Daniel Shub
Daniel Shub 2011-3-8
Seems like this might be related to the polynomial class example included in the OOP guide
web([docroot '/techdoc/matlab_oop/f3-39071.html'])

类别

在 Help Center 和 File Exchange 中查找有关 Symbolic Math Toolbox 的更多信息

标签

Community Treasure Hunt

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

Start Hunting!

Translated by