data fitting to equation

2 次查看（过去 30 天）
Sudhir Rai
Sudhir Rai 2020-8-20
评论： Walter Roberson 2023-1-10
@Matt J,@Walter Roberson
I have data for time(t) and pressure (p).
I want to fit these data to equation
I have done simple calcualtion and fittings in matlab. plese suggest how to fit data.
  12 个评论
显示 10更早的评论
Sudhir Rai
Sudhir Rai 2023-1-10
d is constant that is length of diffusion . range of C_1, c_2 :
c_1 =1e-13 to 1e-17 and c_2=1e-9 to 1e-11 approximatly.
d is ~ 1e-4
Sudhir Rai
Sudhir Rai 2023-1-10
t is time which could go upto 2000 s

请先登录，再进行评论。

请先登录，再回答此问题。

回答（1 个）

Just Manuel
Just Manuel 2021-2-24
Refer to this answer from Star Strider:
https://ch.mathworks.com/matlabcentral/answers/126146-curve-fitting-without-the-toolbox
You can fit any function using simple least squares regression. Just formulate your function (i guess you have already done that) in matlab, then make a cost function (least squares) and use fminsearch to optimize parameters c1 and c2
P = @(c, t) ... % your function
cost = @(c) sum((P(c,t) - p).^2);
% guess initial parameters
c_guess = [1 1];
% use fminsearch
c = fminsearch(cost, guess);
Cheers
Manuel
  2 个评论
Sudhir Rai
Sudhir Rai 2023-1-10
I am using for loop for my function. But I am facing problem in using loop output with fminsearch.
and it is not optimizing my parameters.
Could you help me with it?
Walter Roberson
Walter Roberson 2023-1-10
Your code 2 1/2 years ago did not involve fmincon at all, so we cannot guess what your current code looks like.

请先登录，再进行评论。

类别

在 Help Center 和 File Exchange 中查找有关 Interpolation 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