Differential Equations and Variables
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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
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Accepted Answer
Yao Li
on 10 Apr 2013
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 Comments
Yao Li
on 10 Apr 2013
Edited: Yao Li
on 10 Apr 2013
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
on 10 Apr 2013
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.
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