Solving ODEs with large parameters in Mathematica 9

In summary, the conversation discusses a specific ODE involving known and unknown functions, as well as an adjustable parameter. The individual is using ParametricNDSolve to solve for the interpolation of the unknown function, but is having difficulties when the parameter is large. They are wondering if there is a way to work around this issue.
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WannabeNewton
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I have an ODE ##e^{2x}H(Hv'(x) + H'v' + Hv'') + (k^2 - 2e^{2x}H^2(1 + \frac{H'}{2H}))v = 0## where ##H(x)## is a known function that Mathematica has stored as an interpolation from a previous ODE and ##v(x)## is the unknown function to be solved for. ##k## is the adjustable parameter. Using ParametricNDSolve, Mathematica has no problem solving for an interpolation of ##v## if ##k## is very small e.g. on the order of ##10^{-3}## or even on the order of unity. But I have to solve for ##v## using values of ##k## that are of the order ##10^7## to ##10^{12}##. Right now I'm running ParametricNDSolve for ##k \sim 10^7## and it is taking ages to solve for ##v##. In fact I don't know if it actually will eventually solve for ##v## in a reasonable amount of time. If it doesn't solve it in a reasonable amount of time then I have no hope of ParametricNDSolve solving it in uniform steps between ##k \sim 10^7## and ##k \sim 10^{12}##. Is there a reasonable way to work around this?
 
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What are Ordinary Differential Equations (ODEs)?

ODEs are mathematical equations that describe the relationship between a function and its derivatives. They are commonly used in scientific and engineering fields to model change and behavior over time.

How does Mathematica 9 solve ODEs with large parameters?

Mathematica 9 uses numerical methods to solve ODEs with large parameters. These methods involve breaking down the ODE into smaller, simpler equations that can be solved using algorithms and computer calculations.

What are some common challenges in solving ODEs with large parameters?

One common challenge is the stiffness of the ODE, where the solution changes rapidly in a small interval. This can lead to numerical errors and require more advanced methods to accurately solve the ODE. Another challenge is choosing appropriate initial conditions and parameters, as they can greatly affect the solution.

Can Mathematica 9 solve ODEs with discontinuous or piecewise functions?

Yes, Mathematica 9 has the ability to handle discontinuous or piecewise functions in ODEs. This can be done by using the WhenEvent function, which allows for the specification of conditions and actions to be taken when those conditions are met.

Are there any resources available for learning how to solve ODEs with large parameters in Mathematica 9?

Yes, there are many online tutorials, forums, and user guides that can help you learn how to solve ODEs with large parameters in Mathematica 9. The official Mathematica website also provides documentation and examples for using the software to solve ODEs.

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