d02 Chapter Contents
d02 Chapter Introduction
NAG C Library Manual

# NAG Library Function Documentnag_dae_ivp_dassl_linalg (d02npc)

## 1  Purpose

nag_dae_ivp_dassl_linalg (d02npc) is a setup function which you must call prior to nag_dae_ivp_dassl_gen (d02nec) and after a call to nag_dae_ivp_dassl_setup (d02mwc), if the Jacobian is to be considered as having a banded structure.

## 2  Specification

 #include #include
 void nag_dae_ivp_dassl_linalg (Integer neq, Integer ml, Integer mu, Integer icom[], Integer licom, NagError *fail)

## 3  Description

A call to nag_dae_ivp_dassl_linalg (d02npc) specifies that the Jacobian to be used is banded in structure. If nag_dae_ivp_dassl_linalg (d02npc) is not called before a call to nag_dae_ivp_dassl_gen (d02nec) then the Jacobian is assumed to be full.

None.

## 5  Arguments

1:     neqIntegerInput
On entry: the number of differential-algebraic equations to be solved.
Constraint: $1\le {\mathbf{neq}}$.
2:     mlIntegerInput
On entry: $ml$, the number of subdiagonals in the band.
Constraint: $0\le {\mathbf{ml}}\le {\mathbf{neq}}-1$.
3:     muIntegerInput
On entry: $mu$, the number of superdiagonals in the band.
Constraint: $0\le {\mathbf{mu}}\le {\mathbf{neq}}-1$.
4:     icom[licom]IntegerCommunication Array
icom is used to communicate details of the integration from nag_dae_ivp_dassl_setup (d02mwc) and details of the banded structure of the Jacobian to nag_dae_ivp_dassl_gen (d02nec).
5:     licomIntegerInput
On entry: the dimension of the array icom.
Constraint: ${\mathbf{licom}}\ge 50+{\mathbf{neq}}$.
6:     failNagError *Input/Output
The NAG error argument (see Section 3.6 in the Essential Introduction).

## 6  Error Indicators and Warnings

On entry, argument $〈\mathit{\text{value}}〉$ had an illegal value.
NE_INITIALIZATION
Either the initialization function has not been called prior to the first call of this function or the communication array has become corrupted.
NE_INT
On entry, licom is too small: ${\mathbf{licom}}=〈\mathit{\text{value}}〉$.
On entry, ${\mathbf{ml}}=〈\mathit{\text{value}}〉$.
Constraint: ${\mathbf{ml}}\ge 0$.
On entry, ${\mathbf{mu}}=〈\mathit{\text{value}}〉$.
Constraint: ${\mathbf{mu}}\ge 0$.
On entry, ${\mathbf{neq}}=〈\mathit{\text{value}}〉$.
Constraint: ${\mathbf{neq}}\ge 1$.
NE_INT_2
On entry, ${\mathbf{ml}}=〈\mathit{\text{value}}〉$ and ${\mathbf{neq}}-1=〈\mathit{\text{value}}〉$.
Constraint: ${\mathbf{ml}}\le {\mathbf{neq}}-1$.
On entry, ${\mathbf{mu}}=〈\mathit{\text{value}}〉$ and ${\mathbf{neq}}-1=〈\mathit{\text{value}}〉$.
Constraint: ${\mathbf{mu}}\le {\mathbf{neq}}-1$.
NE_INTERNAL_ERROR
An internal error has occurred in this function. Check the function call and any array sizes. If the call is correct then please contact NAG for assistance.

Not applicable.