Differential Equations and Variables

1 次查看（过去 30 天）
J
J 2013-4-10
Hello,
I would like to know if it's possible to execute and store results from a simple linear differential equation pulling one of the variable from an external file and storing/saving the results in a different file keeping the same formatting.
To better explain, here is what I am trying to do:
I have a table in excel, column 'I' is one of the variable in my model where values change. I need to compute the results of my differential equation so that the result can be inserted next to each of the cells of 'I'
'I' is the variable which would actually vary in my case
my diff equations is: dx/dt=I(S+A).
Thank you regards J

请先登录，再回答此问题。

采纳的回答

Yao Li
Yao Li 2013-4-10
I=xlsread('Path\filename.xlsx','I:I');
%add your own codes to solve the equation
n=length(I);
range=strcat('J1:J',num2str(n));
xlswrite('Path\filename.xlsx',output,range);
  7 个评论
显示 5更早的评论
Yao Li
Yao Li 2013-4-10
编辑：Yao Li 2013-4-10
Assuming I, S and A are stored in columns A,B and C, respectively. The results x will be stored in column D. Hope the codes below can help:
data=xlsread('Path\filename.xlsx','A:C');
I=data(:,1);
S=data(:,2);
A=data(:,3);
time=(30:30:48*60)';
n=length(time);
range=strcat('D1:D',num2str(n));
x0=1;
x(1)=x0;
for i=2:1:n
c(i)=trapz(time(1:i),(I(1:i).*(S(1:i)+A(1:i))));
x(i)=x0*exp(c(i));
end
xlswrite('Path\filename.xlsx',x',range);
Pls. pay attention to the x' in the last row.
Yao Li
Yao Li 2013-4-10
Actually, I think you can also import your data to Simulink to obtain your outputs. If you think it's OK, you can send the Excel file to me by email.

请先登录，再进行评论。

更多回答（0 个）

类别

在 Help Center 和 File Exchange 中查找有关 Ordinary Differential Equations 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