Error with calling out ODE Function for my Code
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Hi All,
I'm trying to get my code to run. It's supposed to call out my odefun1 function and use it for the ODE113 solver. But I'm getting an error stating:
Undefined function 'X_0' for input arguments of type 'double'.
Error in odefun1 (line 3) x_1 = X_0(1);
Error in odearguments (line 88) f0 = feval(ode,t0,y0,args{:}); % ODE15I sets args{1} to yp0.
Error in ode113 (line 114) [neq, tspan, ntspan, next, t0, tfinal, tdir, y0, f0, odeArgs, odeFcn, ...
Error in HW4 (line 11) [t,y] = ode113(@odefun1, tspan, X_0); %calls ODE113
My function file is saved as odefun1.m with the following code: function ydot = odefun1(t,y)
x_1 = X_0(1);
y_1 = X_0(2);
z_1 = X_0(3);
x_2 = X_0(4);
y_2 = X_0(5);
z_2 = X_0(6);
mu = 0.012; %mass ratio for Earth-Moon System
r_1 = sqrt((x_1+mu)^2 + y_1^2 + z_1^2);
r_2 = sqrt((x_1-1+mu)^2 + y_1^2 + z_1^2);
ydot(1,1) = x_2;
ydot(2,1) = y_2;
ydot(3,1) = z_2;
ydot(4,1) = x_1-((1-mu)*(x_1+mu)/r_1^3)-(mu*(x_1-1+mu)/r_2^3)+(2*y_2);
ydot(5,1) = y_1-((1-mu)*y_1/r_1^3)-(mu*y_1/r_2^3)-(2*x_2);
ydot(6,1) = -((1-mu)*z_1/r_1^3)-(mu*z_1/r_2^3);
I tried calling it from another mfile using:
t_0 = 0;
t_f = 5.906784808167686;
tspan = [t_0 t_f]; %time span to integrate over
X_0 = [0.999970555399038; -0.000035183036743; 0; 0.339376400085973; -0.243910167049855; 0]; %initial condition
[t,y] = ode113(@odefun1, tspan, X_0); %calls ODE113
but errors keep popping up. I'm not sure what's wrong. Any help is appreciated!
采纳的回答
Star Strider
2016-9-19
Change the first line of your function file declaration to:
function ydot = odefun1(t,X_0)
and your code works. I leave it to you to determine if it gives the correct result.
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