NAG AD Library
f11bd_a1w_f (real_gen_basic_setup_a1w)

Note: _a1w_ denotes that first order adjoints are computed in working precision; this has the corresponding argument type nagad_a1w_w_rtype. Further implementations, for example for higher order differentiation or using the tangent linear approach, may become available at later marks of the NAG AD Library. The method of codifying AD implementations in the routine name and corresponding argument types is described in the NAG AD Library Introduction.

1 Purpose

f11bd_a1w_f is the adjoint version of the primal routine f11bdf.

2 Specification

Fortran Interface
Subroutine f11bd_a1w_f ( ad_handle, method, precon, norm, weight, iterm, n, m, tol, maxitn, anorm, sigmax, monit, lwreq, work, lwork, ifail)
Integer, Intent (In) :: iterm, n, m, maxitn, monit, lwork
Integer, Intent (Inout) :: ifail
Integer, Intent (Out) :: lwreq
Type (nagad_a1w_w_rtype), Intent (In) :: tol, anorm, sigmax
Type (nagad_a1w_w_rtype), Intent (Out) :: work(lwork)
Character (*), Intent (In) :: method
Character (1), Intent (In) :: precon, norm, weight
Type (c_ptr), Intent (In) :: ad_handle
C++ Header Interface
#include <nagad.h>
void f11bd_a1w_f_ ( void *&ad_handle, const char *method, const char *precon, const char *norm, const char *weight, const Integer &iterm, const Integer &n, const Integer &m, const nagad_a1w_w_rtype &tol, const Integer &maxitn, const nagad_a1w_w_rtype &anorm, const nagad_a1w_w_rtype &sigmax, const Integer &monit, Integer &lwreq, nagad_a1w_w_rtype work[], const Integer &lwork, Integer &ifail, const Charlen length_method, const Charlen length_precon, const Charlen length_norm, const Charlen length_weight)
The routine may be called by the names f11bd_a1w_f or nagf_sparse_real_gen_basic_setup_a1w.

3 Description

f11bd_a1w_f is the adjoint version of the primal routine f11bdf.
f11bdf is a setup routine, the first in a suite of three routines for the iterative solution of a real general (nonsymmetric) system of simultaneous linear equations. f11bdf must be called before f11bef, the iterative solver.
These routines are suitable for the solution of large sparse general (nonsymmetric) systems of equations. For further information see Section 3 in the documentation for f11bdf.

4 References


5 Arguments

In addition to the arguments present in the interface of the primal routine, f11bd_a1w_f includes some arguments specific to AD.
A brief summary of the AD specific arguments is given below. For the remainder, links are provided to the corresponding argument from the primal routine. A tooltip popup for all arguments can be found by hovering over the argument name in Section 2 and in this section.
1: ad_handle – Type (c_ptr) Input
On entry: a handle to the AD configuration data object, as created by x10aa_a1w_f.
2: method – character Input
3: precon – character Input
4: norm – character Input
5: weight – character Input
6: iterm – Integer Input
7: n – Integer Input
8: m – Integer Input
9: tolType (nagad_a1w_w_rtype) Input
10: maxitn – Integer Input
11: anormType (nagad_a1w_w_rtype) Input
12: sigmaxType (nagad_a1w_w_rtype) Input
13: monit – Integer Input
14: lwreq – Integer Output
15: work(lwork) – Type (nagad_a1w_w_rtype) array Communication Array
16: lwork – Integer Input
17: ifail – Integer Input/Output

6 Error Indicators and Warnings

f11bd_a1w_f preserves all error codes from f11bdf and in addition can return:
An unexpected AD error has been triggered by this routine. Please contact NAG.
See Section 4.5.2 in the NAG AD Library Introduction for further information.
Dynamic memory allocation failed for AD.
See Section 4.5.1 in the NAG AD Library Introduction for further information.

7 Accuracy

Not applicable.

8 Parallelism and Performance

f11bd_a1w_f is not threaded in any implementation.

9 Further Comments


10 Example

The following examples are variants of the example for f11bdf, modified to demonstrate calling the NAG AD Library.
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