ODE45 error must return column vector

2023 3 11
1 个回答
回答已采纳
更新时间：2023 3 11
4 次查看（30 天）
Ran in:

0 个投票

Ran in:
No matter what I do I keep receiving the error of a column vector. I have tried making it all zeros first befort completing the function to create a column vector but nothing is working. Any insight would be helpful.
CO(2,1) = 10;
tRange(2,1) = 10;
[tSol,CSol] = ode45(@ConvFunction,tRange,CO);
Error using odearguments
CONVFUNCTION must return a column vector.

Error in ode45 (line 107)
odearguments(odeIsFuncHandle,odeTreatAsMFile, solver_name, ode, tspan, y0, options, varargin);
plot(tSol,CSol(:,1))
function F = ConvFunction(t,~)
CaO=10;
k1=.45;
k2=.05;
Ca=CaO*exp(-t*(k1+k2));
dCadt=-(k1*(Ca)-(k2*(Ca)));
dCbdt=k1*(Ca);
dCcdt=k2*(Ca);
dFdt = zeros(3,1);
dFdt = [dCadt dCbdt dCcdt];
F= dFdt;
end

请先登录，再回答此问题。

 采纳的回答

Paul
Paul 2023-3-11

0 个投票

Try doing what the error message says and make sure that F is a column vector. Here's one option
dFdt = [dCadt ; dCbdt ; dCcdt];
Also, the code is only specifying two initial conditions. It needs to specify three.

2 个评论
显示 无 隐藏 无

Brianna Biondo
Brianna Biondo 2023-3-11
编辑：Brianna Biondo 2023-3-11
Ran in:
Ran in:
Thank you for the help, im getting this as an answer now. Sorry I am newer to matlab and am getting really confused.
CO(2,1) = 10;
tRange(2,1) = 10;
[tSol,CSol,~] = ode45(@ConvFunction,tRange,CO);
Error using odearguments
CONVFUNCTION returns a vector of length 3, but the length of initial conditions vector is 2. The vector returned by CONVFUNCTION and the initial conditions vector must have the same number of
elements.

Error in ode45 (line 107)
odearguments(odeIsFuncHandle,odeTreatAsMFile, solver_name, ode, tspan, y0, options, varargin);
plot(tSol,CSol(:,1))
function F = ConvFunction(t,~,~)
CaO=10;
k1=.45;
k2=.05;
Ca=CaO*exp(-t*(k1+k2));
dCadt=-(k1*(Ca)-(k2*(Ca)));
dCbdt=k1*(Ca);
dCcdt=k2*(Ca);
dFdt = zeros(3,1);
dFdt = [dCadt;dCbdt;dCcdt];
F= dFdt;
end
Walter Roberson
Walter Roberson 2023-3-11
Unless you have assigned something to CO before this,
CO(2,1) = 10;
creates CO as a column vector with exactly two values. You are passing that vector of length 2 as the initial state. You ignore the state inside ConvFunction and return a vector of length 3 . The length of the vector you return must be the same as the number of input values.

请先登录，再进行评论。

更多回答（0 个）

类别

在 帮助中心 和 File Exchange 中查找有关 Image Processing Toolbox 的更多信息

产品

版本

R2022b

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by