XLPack 7.0
XLPack Numerical Library (Excel VBA) Reference Manual
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◆ Contex_r()

Function Contex_r ( I As  Long,
T As  Double,
RCont() As  Double,
ICont() As  Long 
)

Initial value problem of ordinary differential equations (Extrapolation method based on the linearly implicit Euler method) (Interpolation for dense output)

NOTE - THIS PROGRAM IS DEPRECATED AND WILL BE REMOVED IN THE NEXT VERSION.

Purpose
This is the support routine which interpolates the solution for dense output when an initial value problem of a system of ordinary differential equations is solved by Seulex_r.

Seulex_r must be called with Iout = 1 to enable dense output.
When returned from Seulex_r with IRev = 5 after each accepted step, the interpolated solution at any T within latest step interval can be computed by using this routine.
Returns
Double
Interpolated solution Y(I).
Parameters
[in]IElement number of solution to be interpolated. (0 <= I <= N - 1)
[in]TT at which the interpolated solution is computed.
T must be in the interval of the last step. That is, T1 <= T <= T2 where T1 is the value of T on the previous return from Seulex_r with IRev = 5, and T2 is the value on this time.
[in]RCont()Array RCont(LRCont - 1) (LRCont >= (Km + 2)*N)
Control information for dense output.
[in]ICont()Array ICont(LICont - 1) (LICont >= N)
Integer control information for dense output.
Reference
E. Hairer, S.P. Norsett and G. Wanner, "Solving Ordinary Differential Equations II. Stiff and differential-algebraic Problems. 2nd edition", Springer Series in Computational Mathematics, Springer-Verlag (1996)
Example Program
See example program (2) of Seulex_r.