naginterfaces.library.ode.ivp_​stiff_​bandjac_​setup

naginterfaces.library.ode.ivp_stiff_bandjac_setup(neq, neqmax, jceval, ml, mu, nwkjac, njcpvt, comm)

ivp_stiff_bandjac_setup is a setup function which you must call prior to an integrator in submodule ode, if banded matrix linear algebra is required.

For full information please refer to the NAG Library document for d02nt

https://support.nag.com/numeric/nl/nagdoc_30/flhtml/d02/d02ntf.html

Parameters

neqint

The number of differential equations.

neqmaxint

A bound on the maximum number of differential equations to be solved during the integration.

jcevalstr, length 1

Specifies the technique to be used to compute the Jacobian as follows:

$jceval=\text{'N'}$

The Jacobian is to be evaluated numerically by the integrator. If this option is used, the actual argument corresponding to $\text{jac}$ in the call to ivp_stiff_exp_bandjac() or ivp_stiff_imp_bandjac() must be specified as None.

$jceval=\text{'A'}$

You must supply a (sub)program to evaluate the Jacobian on a call to the integrator.

$jceval=\text{'D'}$

The default choice is to be made. In this case ‘D’ is interpreted as ‘N’.

Only the first character of the actual argument $jceval$ is passed to ivp_stiff_bandjac_setup; hence it is permissible for the actual argument to be more descriptive, e.g., ‘Numerical’, ‘Analytical’ or ‘Default’, on a call to ivp_stiff_bandjac_setup.

mlint

$m_L$, the number of subdiagonals in the band.

muint

$m_U$, the number of superdiagonals in the band.

nwkjacint

The size of the workspace array $\text{wkjac}$, which you are supplying to the integrator, as declared in the (sub)program from which ivp_stiff_bandjac_setup is called.

njcpvtint

The size of the workspace array $\text{jacpvt}$, which you are supplying to the integrator, as declared in the (sub)program from which ivp_stiff_bandjac_setup is called.

commdict, communication object, modified in place

Communication structure.

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

Raises

NagValueError

(errno $1$)

On entry, $jceval=⟨value⟩$.

Constraint: $jceval=\text{'A'}$, $\text{'N'}$ or $\text{'D'}$.

(errno $1$)

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

Constraint: $mu\le neq-1$.

(errno $1$)

On entry, $mu=⟨value⟩$.

Constraint: $mu\ge 0$.

(errno $1$)

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

Constraint: $ml\le neq-1$.

(errno $1$)

On entry, $ml=⟨value⟩$.

Constraint: $ml\ge 0$.

(errno $1$)

On entry, $nwkjac=⟨value⟩$, $ml=⟨value⟩$, $mu=⟨value⟩$ and $neqmax=⟨value⟩$.

Constraint: $nwkjac\ge (2\times ml+mu+1)\times neqmax$.

(errno $1$)

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

Constraint: $njcpvt\ge neqmax$.

(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_bandjac_setup defines the linear algebra to be used as banded matrix linear algebra, permits you to specify the method for calculating the Jacobian and checks the validity of certain input values.