solve second order ode system numerically
2 visualizaciones (últimos 30 días)
Mostrar comentarios más antiguos
hosein Javan
el 24 de Oct. de 2018
Comentada: Maxime Sabet D'Acre
el 11 de Nov. de 2020
hello I'm trying to solve this system of second order ordinary differential equations using ode functions (not dsolve):
k1*x' + k2*y' + k3*x + k4*y = u
k5*x" + k6*y" + k7*y' + k8*y = 0
is there a way to convert this system to first order system of equations like in "odeToVectorField"? also is there a function that acts inversely? (like a "VectorFieldToode") to combine the two equations into one higher order differential equation.
0 comentarios
Respuesta aceptada
Star Strider
el 24 de Oct. de 2018
I would normally expect this to work for other systems of differential equations:
syms k1 k2 k3 k4 k5 k6 k7 k8 u x(t) y(t) Y
Dx = diff(x);
D2x = diff(Dx);
Dy = diff(y);
D2y = diff(Dy);
Eqn1 = k1*Dx + k2*Dy + k3*x + k4*y == u;
Eqn2 = k5*D2x + k6*D2y + k7*Dy + k8*y == 0;
[VF,Subs] = odeToVectorField(Eqn1, Eqn2)
odeFcn = matlabFunction(VF, 'Vars',{t, Y, u, [k1, k2, k3, k4, k5, k6, k7, k8]})
However, that code throws this error:
Error using mupadengine/feval (line 187)
Number of indeterminates exceeds the number of ODEs.
I must leave it to you to resolve that problem.
3 comentarios
Star Strider
el 24 de Oct. de 2018
As always, my pleasure!
Actually, it is not a bug. You changed your system of differential equations, and the condition that threw the original error was no longer present.
Más respuestas (0)
Ver también
Categorías
Más información sobre Ordinary Differential Equations en Help Center y File Exchange.
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!