XLPack 6.1
C/C++ API Reference Manual
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◆ _dverk_int()

void _dverk_int ( int  n,
double  t,
double  y[],
double  c[],
double  work[] 
)

Initial value problem of ordinary differential equations (6(5)-th order Runge-Kutta-Verner method) (Interpolation for dense output)

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 dverk. For the details of interpolants used here, refer to the reference below.

dverk must be called with setting parameter c[8] = 2 to enable dense output. Note that larger work array work[] is required. Further, one additional function evaluation per accepted step is required.
When returned from dverk with ind = 5 (ind = 3 for last step) after accepted step, the interporated solution within last step interval can be computed by using this routine.
Parameters
[in]nNumber of differential equations. (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 dverk with ind = 5, and t2 is the value on the last return with info = 5.
[out]y[]Array y[ly] (ly >= n)
Interpoolated solution at t.
[in]c[]Array c[lc]
Parameter array c[] used by dverk.
[in]work[]Array work[lwork]
Work array work[] used by dverk.
Reference
W H Enright et al. "Interpolants for Runge-Kutta Formulas" ACM Transactions on Mathematical Software Vol.12, No.3, 1986, pp.193-218