NAG FL Interface
f11jpf (complex_​herm_​precon_​ilu_​solve)

1 Purpose

2 Specification

3 Description

4 References

5 Arguments

1: $\mathbf{n}$ – Integer Input

On entry: $n$, the order of the matrix $M$. This must be the same value as was supplied in the preceding call to f11jnf.

Constraint: $\mathbf{n}\ge 1$.

2: $\mathbf{a}\left(\mathbf{la}\right)$ – Complex (Kind=nag_wp) array Input

On entry: the values returned in the array a by a previous call to f11jnf.

3: $\mathbf{la}$ – Integer Input

On entry: the dimension of the arrays a, irow and icol as declared in the (sub)program from which f11jpf is called. This must be the same value supplied in the preceding call to f11jnf.

4: $\mathbf{irow}\left(\mathbf{la}\right)$ – Integer array Input

5: $\mathbf{icol}\left(\mathbf{la}\right)$ – Integer array Input

6: $\mathbf{ipiv}\left(\mathbf{n}\right)$ – Integer array Input

7: $\mathbf{istr}\left(\mathbf{n}+1\right)$ – Integer array Input

On entry: the values returned in arrays irow, icol, ipiv and istr by a previous call to f11jnf.

8: $\mathbf{check}$ – Character(1) Input

On entry: specifies whether or not the input data should be checked.

$\mathbf{check}=\text{'C'}$

Checks are carried out on the values of n, irow, icol, ipiv and istr.

$\mathbf{check}=\text{'N'}$

None of these checks are carried out.

Constraint: $\mathbf{check}=\text{'C'}$ or $\text{'N'}$.

9: $\mathbf{y}\left(\mathbf{n}\right)$ – Complex (Kind=nag_wp) array Input

On entry: the right-hand side vector $y$.

10: $\mathbf{x}\left(\mathbf{n}\right)$ – Complex (Kind=nag_wp) array Output

On exit: the solution vector $x$.

11: $\mathbf{ifail}$ – Integer Input/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 4 in the Introduction to the NAG Library FL Interface 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, $\mathbf{check}=〈\mathit{\text{value}}〉$.
Constraint: $\mathbf{check}=\text{'C'}$ or $\text{'N'}$.

$\mathbf{ifail}=2$

On entry, $\mathbf{n}=〈\mathit{\text{value}}〉$.
Constraint: $\mathbf{n}\ge 1$.

$\mathbf{ifail}=3$

On entry, $\mathbf{a}\left(i\right)$ is out of order: $i=〈\mathit{\text{value}}〉$.

On entry, $\mathit{I}=〈\mathit{\text{value}}〉$, $\mathbf{icol}\left(\mathit{I}\right)=〈\mathit{\text{value}}〉$ and $\mathbf{irow}\left(\mathit{I}\right)=〈\mathit{\text{value}}〉$.
Constraint: $\mathbf{icol}\left(\mathit{I}\right)\ge 1$ and $\mathbf{icol}\left(\mathit{I}\right)\le \mathbf{irow}\left(\mathit{I}\right)$.

On entry, $i=〈\mathit{\text{value}}〉$, $\mathbf{ipiv}\left(i\right)=〈\mathit{\text{value}}〉$, $\mathbf{n}=〈\mathit{\text{value}}〉$.
Constraint: $\mathbf{ipiv}\left(i\right)\ge 1$ and $\mathbf{ipiv}\left(i\right)\le \mathbf{n}$.

On entry, $i=〈\mathit{\text{value}}〉$, $\mathbf{irow}\left(i\right)=〈\mathit{\text{value}}〉$ and $\mathbf{n}=〈\mathit{\text{value}}〉$.
Constraint: $\mathbf{irow}\left(i\right)\ge 1$ and $\mathbf{irow}\left(i\right)\le \mathbf{n}$.

On entry, $\mathbf{ipiv}\left(i\right)$ is a repeated value: $i=〈\mathit{\text{value}}〉$.

On entry, istr appears to be invalid.

On entry, $\mathbf{istr}\left(i\right)$ is inconsistent with irow: $i=〈\mathit{\text{value}}〉$.

On entry, the location ($\mathbf{irow}\left(\mathit{I}\right),\mathbf{icol}\left(\mathit{I}\right)$) is a duplicate: $\mathit{I}=〈\mathit{\text{value}}〉$.

Check that a, irow, icol, ipiv and istr have not been corrupted between calls to f11jnf and f11jpf.

$\mathbf{ifail}=-99$

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

See Section 7 in the Introduction to the NAG Library FL Interface for further information.

$\mathbf{ifail}=-399$

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

See Section 8 in the Introduction to the NAG Library FL Interface for further information.

$\mathbf{ifail}=-999$

Dynamic memory allocation failed.

See Section 9 in the Introduction to the NAG Library FL Interface for further information.

7 Accuracy

8 Parallelism and Performance

9 Further Comments

9.1 Timing

10 Example

10.1 Program Text

10.2 Program Data

10.3 Program Results