d02ptc provides details about an integration performed by either
d02pec,
d02pfc or
d02pgc.
d02ptc and its associated functions (
d02pec,
d02pfc,
d02pgc,
d02phc,
d02pjc,
d02pqc,
d02prc,
d02psc and
d02puc) solve the initial value problem for a first-order system of ordinary differential equations. The functions, based on Runge–Kutta methods and derived from RKSUITE (see
Brankin et al. (1991)), integrate
where
$y$ is the vector of
$n$ solution components and
$t$ is the independent variable.
After a call to
d02pec,
d02pfc or
d02pgc,
d02ptc can be called to obtain information about the cost of the integration and the size of the next step.
Brankin R W, Gladwell I and Shampine L F (1991) RKSUITE: A suite of Runge–Kutta codes for the initial value problems for ODEs SoftReport 91-S1 Southern Methodist University
Not applicable.
When a secondary integration has taken place, that is when global error assessment has been specified using
${\mathbf{errass}}=\mathrm{Nag\_ErrorAssess\_on}$
in a prior call to
d02pqc, then the approximate number of evaluations of
$f$ used in this secondary integration is given by
$2\times {\mathbf{stepsok}}\times {\mathbf{stepcost}}$ for
${\mathbf{method}}=\mathrm{Nag\_RK\_4\_5}$ or
$\mathrm{Nag\_RK\_7\_8}$ and
$3\times {\mathbf{stepsok}}\times {\mathbf{stepcost}}$ for
${\mathbf{method}}=\mathrm{Nag\_RK\_2\_3}$.