- Use variable instead of y(1),y(2) for long code
- Why not define f function as you did before?
using shooting method for coupled ode
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Hi all,
please help,I'm looking to solve the following system of equations with boundary conditions using the shooting method:
The equation and m-file attached .
I've found the solution using the BVP4C solver but need to also be able to find the solution using the shooting method.
I'm really quite new to MATLAB and don't really know where to start!
Any help anyone can give me would be greatly appreciated. Thanks!
1 个评论
darova
2020-4-13
Can you rewrite this part?
function f= projfun(x,y)
f= [y(2)
y(1)*y(3)+x*y(2)*y(3)+y(1)*y(2)+(y(9)*(1/alfa*Pr*x))-(y(2)/x)-(y(1)/(x*x))
(-1/x)*(4*y(3)+y(2)+(y(1)/x))
4*y(3)*y(3)+((x*y(3)+y(1)-(1/x))*((-1/x)*(4*y(3)+y(2)+(y(1)/x))))
y(6)
Pr*x*y(3)*y(6)+Pr*y(1)*y(6)-(y(6)/x)
y(8)
(1/B*Tinf)*(alfa*Pr*y(1)*y(8)+alfa*Pr*x*y(3)*y(8)-(((DT*Bs*Fiinf)/(Tinf*Dfi))*((Pr*x*y(3)*y(6)+Pr*y(1)*y(6)-(y(6)/x))-(y(6)/x))))
y(9)
];
end
To make it look like:
function f= projfun(x,y)
E
E = y(1);
dE = y(2);
F = y(3);
dF = y(4);
% ...
f = zeros(9,1);
f(1) = dF;
f(2) = long_expr1;
f(3) = long_expr2;
% ...
end
example
[1 - 2; 2] % work
[1 -2; 2] % doesn't work
I can't check your function because it's difficult to read. I don't want to write new one
回答(1 个)
darova
2020-4-14
编辑:darova
2020-4-14
Thank you more readable code
Here are some mistakes
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/284490/image.png)
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/284491/image.png)
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/284492/image.png)
Some note:
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/284493/image.png)
Shouldn't last equations be like this? What is g? There is no g in your equations
% g = y(7);
E = y(7);
dE = y(8);
% dy(7) = dg;
dy(7) = -1*(4*E+df+f); % E'
dy(8) = (4*E*E)+((E*x+f-1)*(-1*(4*E+df+f))); % E''
You can just use nested functions
function proj
% global variables - no need
% code
function dy = projfun(x,y)
% global variables - no need
% code
end
end
另请参阅
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