Wednesday, April 30, 2014

Generalized Runge Kutta Formulation

For RK methods of order 4 and higher, the inter-stage vectors (k’s) can be represented using the following formulation (Atkinson et al, Numerical Solution of ODE’s):

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The solution at t(n+1) is given by

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J.C. Butcher (Numerical Methods for ODE’s, 2nd Edition) invented the “Butcher tableau” methodology of representing the coefficients a(i,j), b(j) and c(j) for the Runge Kutta methods. The general format of such a tableau is

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 The Butcher tableau for the most popular RK4 method thus becomes:

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The use of the Butcher tableau, along with the generalized formulation from Atkinson, provides an easy methodology for numerical integration of ODEs.

10 comments:

  1. […] the table below (ref: Hairer, Nørsett & Wanner, Solving ODEs, Vol. 1, Non-stiff problems). The generalized formulation can once again be used to solve the initial value […]

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  2. […] Generalized RK formulation can then be used to solve a set of […]

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  3. […] calculations for ki’s and y(n+1) remain the same from the Generalized RK procedure. The error estimation equation is defined […]

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  4. […] estimation (and control) is performed by using two separate calculations with coefficients from the Butcher table as described in the Merson’s method. Having calculated y(n+1) and […]

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  5. […] generalized RK method can then be used with the Kaps-Rentrop algorithm for adaptive step size to solve […]

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  6. […] again, the generalized RK methodology can be used quite easily with the above table for the Verner’s method. The error […]

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  7. […] above representation tends to look more like the generalized RK methods, with the obvious exception of the ‘A’ matrix and the […]

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  8. […] matrix A is the same as the one defined earlier. The step-by-step process (which is similar to the generalized RK methods) can be summarized […]

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  9. […] to the dependent variables (ref: Shampine & Reichelt, The Matlab ODE Suite). Much like the Generalized Runge Kutta methods, the Rosenbrock methods are also explicit single-step formulations that require an […]

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  10. […] Jacobians for more exact solutions, is the higher order Rosenbrock method worth the effort. The explicit RK method is potentially a much easier algorithm to implement. But does it fare as well as the Rosenbrock […]

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