NAG FL Interface
d02mzf (ivp_​stiff_​interp)

1 Purpose

2 Specification

3 Description

4 References

5 Arguments

1: $\mathbf{tsol}$ – Real (Kind=nag_wp) Input

On entry: the point at which the first m components of the solution are to be evaluated. tsol should not normally be an extrapolation point. Extrapolation is permitted but not recommended.

2: $\mathbf{sol}\left(\mathbf{m}\right)$ – Real (Kind=nag_wp) array Output

On exit: the calculated value of the solution at tsol.

3: $\mathbf{m}$ – Integer Input

On entry: the number of components of the solution whose values are required.

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

4: $\mathbf{ldysav}$ – Integer Input

On entry: the value used for the argument ldysav when calling the integrator.

Constraint: $\mathbf{ldysav}\ge \mathbf{neq}$.

5: $\mathbf{neq}$ – Integer Input

On entry: the value used for the argument neq when calling the integrator.

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

6: $\mathbf{ysav}\left(\mathbf{ldysav},\mathbf{sdysav}\right)$ – Real (Kind=nag_wp) array Communication Array

On entry: the values provided in the array ysav on return from the integrator.

7: $\mathbf{sdysav}$ – Integer Input

On entry: the value used for the argument sdysav when calling the integrator.

8: $\mathbf{rwork}\left(50+4\times \mathbf{neq}\right)$ – Real (Kind=nag_wp) array Communication Array

On entry: the values provided in the array rwork on return from the integrator.

9: $\mathbf{ifail}$ – Integer Input/Output

On entry: ifail must be set to $0$, $-1$ or $1$ to set behaviour on detection of an error; these values have no effect when no error is detected.

A value of $0$ causes the printing of an error message and program execution will be halted; otherwise program execution continues. A value of $-1$ means that an error message is printed while a value of $1$ means that it is not.

If halting is not appropriate, the value $-1$ or $1$ is recommended. If message printing is undesirable, then the value $1$ is recommended. Otherwise, the value $0$ is recommended. When the value $-\mathbf{1}$ 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, $\mathbf{ldysav}=〈\mathit{\text{value}}〉$.
Constraint: $\mathbf{ldysav}\ge 1$.

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

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

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

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

$\mathbf{ifail}=2$

Either the integrator function has not been called prior to the first call of this function or the array has become corrupted.

$\mathbf{ifail}=3$

On entry, tsol is an extrapolation point.

On entry, d02mzf has been called for extrapolation. Before returning with this error exit, the value of the solution at tsol is calculated and placed in sol.

$\mathbf{ifail}=-99$

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

10 Example

10.1 Program Text

10.2 Program Data

10.3 Program Results