NAG Library Routine Document

D02NPF

1  Purpose

2  Specification

3  Description

4  References

5  Parameters

1:     NEQ – INTEGERInput

On entry: the number of differential-algebraic equations to be solved.

Constraint: $1\le \mathbf{NEQ}$.

2:     ML – INTEGERInput

On entry: $m_L$, the number of subdiagonals in the band.

Constraint: $0\le \mathbf{ML}\le \mathbf{NEQ}-1$.

3:     MU – INTEGERInput

On entry: $m_U$, the number of superdiagonals in the band.

Constraint: $0\le \mathbf{MU}\le \mathbf{NEQ}-1$.

4:     ICOM(LICOM) – INTEGER arrayCommunication Array

ICOM is used to communicate details of the integration from D02MWF and details of the banded structure of the Jacobian to D02NEF.

5:     LICOM – INTEGERInput

On entry: the dimension of the array ICOM as declared in the (sub)program from which D02NPF is called.

Constraint: $\mathbf{LICOM}\ge 50+\mathbf{NEQ}$.

6:     IFAIL – INTEGERInput/Output

On entry: IFAIL must be set to $0$, $-1\text{ or }1$. If you are unfamiliar with this parameter you should refer to Section 3.3 in the Essential Introduction for details.

For environments where it might be inappropriate to halt program execution when an error is detected, the value $-1\text{ or }1$ is recommended. If the output of error messages is undesirable, then the value $1$ is recommended. Otherwise, if you are not familiar with this parameter, the recommended value is $0$. When the value $-\mathbf{1}\text{ or }\mathbf{1}$ is used it is essential to test the value of IFAIL on exit.

On exit: $\mathbf{IFAIL}=\mathbf{0}$ unless the routine detects an error or a warning has been flagged (see Section 6).

6  Error Indicators and Warnings

$\mathbf{IFAIL}=1$

On entry,

$\mathbf{NEQ}<1$.

$\mathbf{IFAIL}=2$

On entry,

$\mathbf{ML}<0$ or $\mathbf{ML}>\mathbf{NEQ}-1$.

$\mathbf{IFAIL}=3$

On entry,

$\mathbf{MU}<0$ or $\mathbf{MU}>\mathbf{NEQ}-1$.

$\mathbf{IFAIL}=4$

Either D02MWF has not been called before this call or the communication array ICOM has been corrupted.

$\mathbf{IFAIL}=5$

On entry,

$\mathbf{LICOM}<50+\mathbf{NEQ}$.

7  Accuracy

8  Further Comments

9  Example