# naginterfaces.library.ode.ivp_​2nd_​rkn_​diag¶

naginterfaces.library.ode.ivp_2nd_rkn_diag(neq, comm)[source]

ivp_2nd_rkn_diag is a diagnostic function which may be called after a call of the integrator ivp_2nd_rkn().

For full information please refer to the NAG Library document for d02ly

https://www.nag.com/numeric/nl/nagdoc_28.6/flhtml/d02/d02lyf.html

Parameters
neqint

The number of second-order ordinary differential equations solved by ivp_2nd_rkn(). It must be the same as the argument supplied to ivp_2nd_rkn_setup() and ivp_2nd_rkn().

commdict, communication object

Communication structure.

This argument must have been initialized by a prior call to ivp_2nd_rkn_setup().

Returns
hnextfloat

The next step size which ivp_2nd_rkn(), if called, would attempt.

husedfloat

The last successful step size used by ivp_2nd_rkn().

hstartfloat

The initial step size used on the current integration problem by ivp_2nd_rkn().

nsuccint

The number of steps attempted by ivp_2nd_rkn() that have been successful since the start of the current problem.

nfailint

The number of steps attempted by ivp_2nd_rkn() that have failed since the start of the current problem.

nattint

The number of steps attempted before the initial step was successful. Over a large number of problems the cost of an attempted step of this type is approximately half that of a normal attempted step.

thresfloat, ndarray, shape

The th solution threshold value used in the error control strategy. (See ivp_2nd_rkn_setup().)

threspfloat, ndarray, shape

The th derivative threshold value used in the error control strategy. (See ivp_2nd_rkn_setup().)

Raises
NagValueError
(errno )

On entry, , but in the previous call to the setup function .

(errno )

The integrator function ivp_2nd_rkn() has not been called.

Notes

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

ivp_2nd_rkn_diag permits you to extract information about the performance of ivp_2nd_rkn() and the setting of some options. It may be called only after a call of ivp_2nd_rkn().