NAG AD Library
f11be_a1w_f (real_gen_basic_solver_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

f11be_a1w_f is the adjoint version of the primal routine f11bef.

2 Specification

Fortran Interface
Subroutine f11be_a1w_f ( ad_handle, irevcm, u, v, wgt, work, lwork, ifail)
Integer, Intent (In) :: lwork
Integer, Intent (Inout) :: irevcm, ifail
Type (nagad_a1w_w_rtype), Intent (In) :: wgt(*)
Type (nagad_a1w_w_rtype), Intent (Inout) :: u(*), v(*), work(lwork)
Type (c_ptr), Intent (In) :: ad_handle
C++ Header Interface
#include <nagad.h>
void f11be_a1w_f_ ( void *&ad_handle, Integer &irevcm, nagad_a1w_w_rtype u[], nagad_a1w_w_rtype v[], nagad_a1w_w_rtype wgt[], nagad_a1w_w_rtype work[], const Integer &lwork, Integer &ifail)
The routine may be called by the names f11be_a1w_f or nagf_sparse_real_gen_basic_solver_a1w.

3 Description

f11be_a1w_f is the adjoint version of the primal routine f11bef.
f11bef is an iterative solver for a real general (nonsymmetric) system of simultaneous linear equations; f11bef is the second in a suite of three routines, where the first routine, f11bdf, must be called prior to f11bef to set up the suite.
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 f11bef.

4 References

None.

5 Arguments

In addition to the arguments present in the interface of the primal routine, f11be_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: irevcm – Integer Input/Output
3: u(*) – Type (nagad_a1w_w_rtype) array Input/Output
4: v(*) – Type (nagad_a1w_w_rtype) array Input/Output
5: wgt(*) – Type (nagad_a1w_w_rtype) array Input
6: work(lwork) – Type (nagad_a1w_w_rtype) array Communication Array
7: lwork – Integer Input
8: ifail – Integer Input/Output

6 Error Indicators and Warnings

f11be_a1w_f preserves all error codes from f11bef and in addition can return:
ifail=-89
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.
ifail=-899
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

f11be_a1w_f is not threaded in any implementation.

9 Further Comments

None.

10 Example

See Section 10 in f11bd_a1w_f.