NAG Library Routine Document

D02NXF

1  Purpose

2  Specification

3  Description

4  References

5  Parameters

1:     $\mathrm{ICALL}$ – INTEGERInput

On entry: indicates whether or not all output parameters have been set during the call to the integrator. If so, that is, if the integrator returned with $\mathbf{IFAIL}=\mathbf{0}$ or $\mathbf{12}$, then ICALL must be set to $0$. Otherwise ICALL must be set to $1$, indicating that integration did not take place due to lack of space in arrays WKJAC and JACPVT, and only LIWREQ, LIWUSD, LRWREQ, LRWUSD have been set.

2:     $\mathrm{LIWREQ}$ – INTEGEROutput

On exit: the length of the integer workspace JACPVT reserved for the sparse matrix routines.

3:     $\mathrm{LIWUSD}$ – INTEGEROutput

On exit: the length of the integer workspace JACPVT actually used by the sparse matrix routines.

4:     $\mathrm{LRWREQ}$ – INTEGEROutput

On exit: the length of the real workspace WKJAC reserved for the sparse matrix routines.

5:     $\mathrm{LRWUSD}$ – INTEGEROutput

On exit: the length of the real workspace WKJAC actually used by the sparse matrix routines.

6:     $\mathrm{NLU}$ – INTEGEROutput

On exit: the number of $LU$ decompositions done during the integration.

7:     $\mathrm{NNZ}$ – INTEGEROutput

On exit: the number of nonzeros in the Jacobian.

8:     $\mathrm{NGP}$ – INTEGEROutput

On exit: the number of FCN or RESID calls needed to form the Jacobian.

9:     $\mathrm{ISPLIT}$ – INTEGEROutput

On exit: an appropriate value for the parameter ISPLIT when calling D02NUF for subsequent runs of similar problems.

10:   $\mathrm{IGROW}$ – INTEGEROutput

On exit: an estimate of the growth of the elements encountered during the last $LU$ decomposition performed. If the actual estimate exceeds the largest possible integer value for the machine being used (see X02BBF) IGROW is set to the value returned by X02BBF.

11:   $\mathrm{LBLOCK}$ – LOGICALInput

On entry: the value used for the parameter LBLOCK when calling D02NUF.

12:   $\mathrm{NBLOCK}$ – INTEGEROutput

On exit: if $\mathbf{LBLOCK}=\mathrm{.TRUE.}$, NBLOCK contains the number of diagonal blocks in the Jacobian matrix permuted to block lower triangular form. If $\mathbf{NBLOCK}=1$ then on subsequent runs of a similar problem LBLOCK should be set to .FALSE. in the call to D02NUF.

If $\mathbf{LBLOCK}=\mathrm{.FALSE.}$, $\mathbf{NBLOCK}=1$.

13:   $\mathrm{INFORM}\left(23\right)$ – INTEGER arrayCommunication Array

On entry: contains information supplied by the integrator.

6  Error Indicators and Warnings

7  Accuracy

8  Parallelism and Performance

9  Further Comments

10  Example