NAG Library Routine Document

x10bc_a1w_f (callback_mode_set_a1w)

1

Purpose

2

Specification

3

Description

3.1

Life Cycle of the Handle

4

References

5

Arguments

1:     $\mathbf{ad\_handle}$ – Type (c_ptr)Input/Output

On entry: a handle to the AD configuration data object, as created by x10aa_a1w_f.

On exit: holds a handle to the internal data structure where the computational AD configuration data, is defined. You must not change the handle other than via NAG AD Library calls until it is destroyed by x10ab_a1w_f.

2:     $\mathbf{mode}$ – IntegerInput

On entry: the callback computational mode within the current supplied procedure argument.

$\mathbf{mode}=\mathit{nagad\_primal}$

The current callback is expected to perform the primal calculation.

$\mathbf{mode}=\mathit{nagad\_dstate}$

The current callback is expected to return the derivatives of the primal calculation with respect to real-valued input arguments.

$\mathbf{mode}=\mathit{nagad\_dparam}$

The current callback is expected to return the derivatives of the primal calculation with respect to user-supplied real-valued inputs (e.g., in ruser).

$\mathbf{mode}=\mathit{nagad\_dall}$

The current callback is expected to return derivatives of the primal calculation with respect to both active input arguments and active supplied parameters (i.e., combining nagad_dstate and nagad_dparam).

Constraint: $\mathbf{mode}=\mathit{nagad\_primal}$, $\mathit{nagad\_dstate}$, $\mathit{nagad\_dparam}$ or $\mathit{nagad\_dall}$.

3:     $\mathbf{ifail}$ – 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, ad_handle is not a valid handle for the AD computational data object. Either ad_handle has not been initialized or it has become corrupted.

$\mathbf{ifail}=2$

On entry, $\mathbf{mode}=〈\mathit{\text{value}}〉$.
Constraint: $\mathbf{mode}=\mathit{nagad\_primal}$, $\mathit{nagad\_dstate}$, $\mathit{nagad\_dparam}$ or $\mathit{nagad\_dall}$.

$\mathbf{ifail}=-99$

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