Numerical methods for a system of coupled ODE

In summary, the conversation discusses solving a system of coupled ordinary differential equations with arbitrary initial values using discretization and iteration methods. The Runge-Kutta method is mentioned as a potential solution, but it is noted that additional techniques such as the Shooting method may be necessary to handle boundary conditions.
  • #1
Telemachus
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Hi there. I have to solve a system of coupled ordinary differential equations. I have some initial values, but in different points of the domain. The equations are all first order. Let's suppose the system looks like this:

##\displaystyle\frac{dy_1}{dz}=y_1+y_2+0.01##
##\displaystyle\frac{dy_2}{dz}=y_1+y_2+0.01##

with initial conditions: ##y_1(0)=0, y_2(10)=0##

So, I use some discretization in z, and get some iteration scheme that looks like

##y_{1,n+1}=f_1(y_{1,n},y_{2,n})##
##y_{2,n+1}=f_2(y_{1,n},y_{2,n})##

I don't give exactly the recursion formula I've arrivesd I just simplified it to discuss the important aspects, ##f_1## and ##f_2## are just some functions. The thing is, that as you can see, the forward value depends in the current one for both solutions. So, the only way I can get a formula which I can solve is by setting the initial condition at the same point (lets say ##y_1(0)=0## and ##y_2(0)=0##), otherwise, I lack the information necessary to update the values in both solutions.

Does anyone know where I can find some examples on how to solve coupled differential equations with arbitrary initial values?

Best regards.
 
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  • #3
What is the domain of z?
 
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  • #4
Hi, thank you both for your feedback, ##z\in \{0,10\}##

Regarding runge kutta, I could use that, but how would it solve the issue with the boundary conditions?
 
  • #5
Telemachus said:
Hi, thank you both for your feedback, ##z\in \{0,10\}##

Regarding runge kutta, I could use that, but how would it solve the issue with the boundary conditions?

We can combine it with the Shooting method.
 
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FAQ: Numerical methods for a system of coupled ODE

What is a system of coupled ODE?

A system of coupled ODE (ordinary differential equations) is a set of equations where the derivatives of multiple dependent variables are expressed as functions of those variables and independent variables. This means that the variables are interconnected and their values at any given point are dependent on each other.

What are numerical methods for solving a system of coupled ODE?

Numerical methods for solving a system of coupled ODE involve approximating the solutions to the equations at discrete points using numerical techniques. These methods include Euler's method, Runge-Kutta methods, and multistep methods like Adams-Bashforth and Adams-Moulton methods.

How do numerical methods for a system of coupled ODE differ from analytical methods?

Analytical methods for solving a system of coupled ODE involve finding exact solutions using algebraic and calculus techniques. On the other hand, numerical methods approximate the solutions by breaking down the problem into smaller steps and using iterative calculations. This makes numerical methods more suitable for complex systems where analytical solutions may not be possible.

What are the advantages of using numerical methods for a system of coupled ODE?

Numerical methods provide a systematic and efficient way to solve complex systems of equations. They can handle non-linear and time-dependent systems, which may not have analytical solutions. Additionally, numerical methods can handle a large number of equations and variables, making them useful for solving real-world problems in science and engineering.

What are some applications of numerical methods for a system of coupled ODE?

Numerical methods for a system of coupled ODE have various applications in different fields such as physics, chemistry, engineering, and biology. They are used to model and simulate physical systems, analyze chemical reactions, predict weather patterns, and understand biological processes. They are also used in computer graphics and animation to simulate movement and complex interactions between objects.

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