naginterfaces.library.ode.ivp_​stiff_​integ_​diag

naginterfaces.library.ode.ivp_stiff_integ_diag(neq, neqmax, comm)

ivp_stiff_integ_diag is a diagnostic function which you may call either after any user-specified exit or after a mid-integration error exit from 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 d02ny

https://support.nag.com/numeric/nl/nagdoc_30/flhtml/d02/d02nyf.html

Parameters

neqint

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

neqmaxint

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

commdict, communication object

Communication structure.

This argument must have been initialized by a prior call to ivp_stiff_exp_fulljac(), ivp_stiff_exp_bandjac(), ivp_stiff_exp_sparjac(), ivp_stiff_imp_fulljac(), ivp_stiff_imp_bandjac(), ivp_stiff_imp_sparjac(), ivp_stiff_exp_revcom() or ivp_stiff_imp_revcom().

Returns

hufloat

The last successful step size.

hfloat

The proposed next step size for continuing the integration.

tcurfloat

$t$, the value of the independent variable which the integrator has actually reached. $tcur$ will always be at least as far as the output value of the argument $t$ in the direction of integration, but may be further (if overshooting and interpolation at $\text{tout}$ was specified, e.g., see ivp_stiff_exp_fulljac()).

tolsffloat

A tolerance scale factor, $tolsf\ge 1.0$, which is computed when a request for too much accuracy is detected by the integrator (indicated by a return with $errno$ = 3 or 14). If $\text{itol}$ is left unaltered but $\text{rtol}$ and $\text{atol}$ are uniformly scaled up by a factor of $tolsf$ the next call to the integrator is deemed likely to succeed.

nstint

The number of steps taken in the integration so far.

nreint

The number of function or residual evaluations ($\text{fcn}$ (e.g., see ivp_stiff_exp_fulljac()) or $\text{resid}$ (e.g., see ivp_stiff_imp_fulljac()) calls) used in the integration so far.

njeint

The number of Jacobian evaluations used in the integration so far. This equals the number of matrix $LU$ decompositions.

nquint

The order of the method last used (successfully) in the integration.

nqint

The proposed order of the method for continuing the integration.

niterint

The number of iterations performed in the integration so far by the nonlinear equation solver.

imxerint

The index of the component of largest magnitude in the weighted local error vector $\left(e_{\text{i}}/w_{\text{i}}\right)$, for $\text{i}=1,2,\dots ,neq$.

algequbool, ndarray, shape $\left(neq\right)$

$algequ[\text{i}-1]=True$ if the $\text{i}$th equation integrated was detected to be algebraic, otherwise $algequ[\text{i}-1]=False$. Note that when the integrators for explicit equations are being used, then $algequ[\text{i}-1]=False$, for $\text{i}=1,2,\dots ,neq$.

Raises

NagValueError

(errno $1$)

On entry, $neq=⟨value⟩$ and $neqmax=⟨value⟩$.

Constraint: $neq\le neqmax$.

(errno $1$)

On entry, $neqmax=⟨value⟩$.

Constraint: $neqmax\ge 1$.

(errno $1$)

On entry, $neq=⟨value⟩$.

Constraint: $neq\ge 1$.

Notes

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

ivp_stiff_integ_diag permits you to inspect statistics produced by any integrator in this sub-module that has been set up a call to one of ivp_stiff_dassl(), ivp_stiff_bdf() or ivp_stiff_blend(). These statistics concern the integration only.