C Program For Runge Kutta Method

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The Runge-Kutta method is one of several numerical methods of solving differential equations. Some systems motion or process may be governed by differential equations which ar e difficult to. What about a code for Runge Kutta method for second order ODE. Something of this nature: d^2y/dx^2 + 0.6*dy/dx 0.8y = 0.

i'm trying to code a simple runge-kutta method

Below is my 4th order Runge-Kutta algorithm to solve a first order ODE. /* This code is a 1D classical Runge-Kutta method. Compare to the Wikipedia page. The task apparently asked for the 4th order classical Runge-Kutta method of the first tableau. – LutzL Mar 17 '17 at 12:14 @PeterSM.

The function to be approximated and the runge-kutta method are separate definitions, which are called within the loop in the main function.

approximate solutions for y and t are pushed into a separate vectors.

I'm receiving the following errors and struggling to figure out why:Error message snapshot

The code:

Runge Kutta Example

Hariom Singh

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Erez SabranErez Sabran

1 Answer

If you want to use multiple return you can use std::tuple

And returned value can be captured

Error fixed code

drescherjm

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First Order Runge Kutta Method

Hariom SinghHariom Singh

Python Runge Kutta 4th Order

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Your description is just too cryptic: objects with 4 dimensions are few and far between. I suspect now that your DEPENDENT variables are:
- concentration
- species
In other words, X[species i][location j] - that is TWO dimensions.
What you are describing above seems to be the TERMS which COUPLE those equations, which could actually be read, stored and used as a ONE-dimensional array of structs; e.g.
struct process{ int species, in, out; double value; }. When you read them, just assign them sequentially to a vector of structs using push_back(). When you use them in the derivative function just go through them one by one.
If , as I suspect, t is time, you should not be storing that - you should dump your X to file at identified intervals.
It is unclear what you mean by 'convergence'. This version of RK is explicit: there is no in-step iteration. If you meant convergence to final steady state then just use the normed distance between successive values of your dependent-variable array.
I think you need to write down your original equations.