NAG Library Routine Document

d02npf  (dae_dassl_linalg)

1

Purpose

2

Specification

3

Description

4

References

5

Arguments

1:     $\mathbf{neq}$ – IntegerInput

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

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

2:     $\mathbf{ml}$ – IntegerInput

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

Constraint: $0\le \mathbf{ml}\le \mathbf{neq}-1$.

3:     $\mathbf{mu}$ – IntegerInput

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

Constraint: $0\le \mathbf{mu}\le \mathbf{neq}-1$.

4:     $\mathbf{icom}\left(\mathbf{licom}\right)$ – 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:     $\mathbf{licom}$ – 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:     $\mathbf{ifail}$ – IntegerInput/Output

On entry: ifail must be set to $0$, $-1\text{ or }1$. If you are unfamiliar with this argument you should refer to Section 3.4 in How to Use the NAG Library and its Documentation 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 argument, 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, $\mathbf{neq}=〈\mathit{\text{value}}〉$.
Constraint: $\mathbf{neq}\ge 1$.

$\mathbf{ifail}=2$

On entry, $\mathbf{ml}=〈\mathit{\text{value}}〉$.
Constraint: $\mathbf{ml}\ge 0$.

On entry, $\mathbf{ml}=〈\mathit{\text{value}}〉$ and $\mathbf{neq}=〈\mathit{\text{value}}〉$.
Constraint: $\mathbf{ml}\le \mathbf{neq}-1$.

$\mathbf{ifail}=3$

On entry, $\mathbf{mu}=〈\mathit{\text{value}}〉$.
Constraint: $\mathbf{mu}\ge 0$.

On entry, $\mathbf{mu}=〈\mathit{\text{value}}〉$ and $\mathbf{neq}=〈\mathit{\text{value}}〉$.
Constraint: $\mathbf{mu}\le \mathbf{neq}-1$.

$\mathbf{ifail}=4$

Either the initialization routine has not been called prior to the first call of this routine or the communication array has become corrupted.

$\mathbf{ifail}=5$

On entry, licom is too small: $\mathbf{licom}=〈\mathit{\text{value}}〉$.

$\mathbf{ifail}=-99$

An unexpected error has been triggered by this routine. Please contact NAG.

See Section 3.9 in How to Use the NAG Library and its Documentation for further information.

$\mathbf{ifail}=-399$

Your licence key may have expired or may not have been installed correctly.

See Section 3.8 in How to Use the NAG Library and its Documentation for further information.

$\mathbf{ifail}=-999$

Dynamic memory allocation failed.

See Section 3.7 in How to Use the NAG Library and its Documentation for further information.

7

Accuracy

8

Parallelism and Performance

9

Further Comments

10

Example