Using fsolve to generate an array of answers
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Hello,
I am trying to solve two simultaneous equations in a for loop and for each iteration I am changing temperature. I would like to generate an array of solutions such that I can plot verse temperature. Each iteration will generate two values associated with T.
A sample of the code is below:
T2=1809:1:2130; R=8.3144621; x3=[0.5,0.5]; %guess ao_s=18340; ao_l=20000; deltaH_Fe=15200; deltaH_Cr=20900; To_Fe=1809; To_Cr=2130;
for i=1:322
fun3=@(X) [(deltaH_Fe.*(To_Fe-T2(i))./To_Fe)./(R.*T2(i))+(ao_l./R.*... T2(i)).*(X(2).^2)-(ao_s./R.*T2(i)).*(X(1).^2)+log((1-X(2))./(1-X(1)))... ;(deltaH_Cr.*(To_Cr-T2(i))./To_Cr)./(R.*T2(i))+(ao_l./R.*T2(i)).*... ((1-X(2)).^2)-(ao_s./R.*T2(i)).*((1-X(1).^2)+log(X(2)./X(1)))];
X_ph=fsolve(fun3,x3);
end
I would like to generate X_ph either as 2x? matrix depending on how many temperature values or instead generate two separate matrix with values for X(1) in one and X(2) in another.I'm also getting an fsolve stalled error with this currently, not sure why this is happening either...
Any help would be greatly appreciated.
Thank you
1 个评论
Matt Fig
2012-11-3
There is a little button that looks like this: {} Code
Please use it....
采纳的回答
Use this:
X_ph{i}=fsolve(fun3,x3); % Note {} not ()
Now X_ph is a cell array.
help cell
Also, you might be sorry one day that you are masking the MATLAB function i by using this as a variable name.
6 个评论
Mike
2012-11-3
Mike
2012-11-3
Matt Fig
2012-11-3
By using the MATLAB function i as a variable, you are masking the function. Check it out:
clear all
4+5*i % i is a function that returns sqrt(-1)
for i = 1:3,i;end % Now the function is masked. :(
4+5*i % Oops. We needed to use the function...
% Perhaps use k or n instead (j is also a function).
Anyhow, to plot you can extract the X_ph. I didn't run the code, so are the X_ph all the same size?
Mike
2012-11-3
Matt Fig
2012-11-3
So if you want to do:
plot(X_ph,T2)
And you are sure X_ph will return exactly two numbers for each call to fsolve (I didn't run the whole code till the end), the instead of using a cell, use:
X_ph(i,:)=fsolve(fun3,x3);
Now you can plot:
subplot(1,2,1)
plot(X_ph(:,1),T2)
subplot(1,2,2)
plot(X_ph(:,2),T2)
Mike
2012-11-3
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