naginterfaces.library.ode.ivp_​stiff_​contin

naginterfaces.library.ode.ivp_stiff_contin(neqmax, tcrit, h, hmin, hmax, maxstp, mxhnil, comm)

ivp_stiff_contin is a setup function which must be called, if optional inputs need resetting, prior to a continuation call to any of those integrators in submodule ode that use methods set up by calls to ivp_stiff_dassl(), ivp_stiff_bdf() or ivp_stiff_blend().

For full information please refer to the NAG Library document for d02nz

https://support.nag.com/numeric/nl/nagdoc_30.2/flhtml/d02/d02nzf.html

Parameters

neqmaxint

The value used for the argument $neqmax$ when calling the integrator.

tcritfloat

A point beyond which integration must not be attempted. The use of $tcrit$ is described under the argument $\text{itask}$ in the specification for the integrator (e.g., see ivp_stiff_exp_fulljac()). A value, $0.0$ say, must be specified even if $\text{itask}$ subsequently specifies that $tcrit$ will not be used.

hfloat

The next step size to be attempted. Set $h=0.0$ if the current value of $h$ is not to be changed.

hminfloat

The minimum absolute step size to be allowed. Set $hmin=0.0$ if this option is not required. Set $hmin<0.0$ if the current value of $hmin$ is not to be changed.

hmaxfloat

The maximum absolute step size to be allowed. Set $hmax=0.0$ if this option is not required. Set $hmax<0.0$ if the current value of $hmax$ is not to be changed.

maxstpint

The maximum number of steps to be attempted during one call to the integrator after which it will return with $errno$ = 2 (see ivp_stiff_exp_bandjac()). Set $maxstp=0$ if this option is not required. Set $maxstp<0$ if the current value of $maxstp$ is not to be changed.

mxhnilint

The maximum number of warnings printed (if $\text{itrace}\ge 0$, e.g., see ivp_stiff_exp_fulljac()) per problem when $t+h=t$ on a step ($h=\text{current step size}$). If $mxhnil\le 0$, a default value of $10$ is assumed.

commdict, communication object, modified in place

Communication structure.

This argument must have been initialized by a prior call to ivp_stiff_dassl(), ivp_stiff_bdf() or ivp_stiff_blend().

Raises

NagValueError

(errno $1$)

On entry, $neqmax=⟨value⟩$.

Constraint: $neqmax\ge 1$.

Notes

No equivalent traditional C interface for this routine exists in the NAG Library.

ivp_stiff_contin is provided to permit you to reset many of the arguments which control the integration ‘on the fly’, that is in conjunction with the interrupt facility permitted through the argument $\text{itask}$ of the integrator (e.g., see ivp_stiff_exp_fulljac()). In addition to a number of arguments which you can set initially through one of the integrator setup functions, the step size to be attempted on the next step may be changed.