NAG AD Library
e04wb (nlp1_init)

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1 Purpose

e04wb is the AD Library version of the primal routine e04wbf. Based (in the C++ interface) on overload resolution, e04wb can be used for primal, tangent and adjoint evaluation. It supports tangents and adjoints of first and second order.

2 Specification

Fortran Interface
Subroutine e04wb_AD_f ( ad_handle, rname, cwsav, lcwsav, lwsav, llwsav, iwsav, liwsav, rwsav, lrwsav, ifail)
Integer, Intent (In) :: lcwsav, llwsav, liwsav, lrwsav
Integer, Intent (Inout) :: ifail
Integer, Intent (Out) :: iwsav(liwsav)
ADTYPE, Intent (Out) :: rwsav(lrwsav)
Logical, Intent (Out) :: lwsav(llwsav)
Character (*), Intent (In) :: rname
Character (80), Intent (Out) :: cwsav(lcwsav)
Corresponding to the overloaded C++ function, the Fortran interface provides five routines with names reflecting the type used for active real arguments. The actual subroutine and type names are formed by replacing AD and ADTYPE in the above as follows:
when ADTYPE is Real(kind=nag_wp) then AD is p0w
when ADTYPE is Type(nagad_a1w_w_rtype) then AD is a1w
when ADTYPE is Type(nagad_t1w_w_rtype) then AD is t1w
when ADTYPE is Type(nagad_a1t1w_w_rtype) then AD is a1t1w
when ADTYPE is Type(nagad_t2w_w_rtype) then AD is t2w
C++ Interface
#include <dco.hpp>
#include <nagad.h>
namespace nag {
namespace ad {
void e04wb ( const char *rname, char *cwsav[], const Integer &lcwsav, logical lwsav[], const Integer &llwsav, Integer iwsav[], const Integer &liwsav, ADTYPE rwsav[], const Integer &lrwsav, Integer &ifail)
The function is overloaded on ADTYPE which represents the type of active arguments. ADTYPE may be any of the following types:
Note: this function can be used with AD tools other than dco/c++. For details, please contact NAG.

3 Description

e04wb is the AD Library version of the primal routine e04wbf.
e04wbf is used to initialize routines e04dga, e04mfa, e04nca, e04nfa, e04nka, e04uca, e04ufa, e04uga and e04usa. For further information see Section 3 in the documentation for e04wbf.

4 References

5 Arguments

In addition to the arguments present in the interface of the primal routine, e04wb 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: rname – character Input
2: cwsav(lcwsav) – character array Communication Array
3: lcwsav – Integer Input
4: lwsav(llwsav) – logical array Communication Array
5: llwsav – Integer Input
6: iwsav(liwsav) – Integer array Communication Array
7: liwsav – Integer Input
8: rwsav(lrwsav) – ADTYPE array Communication Array
9: lrwsav – Integer Input
10: ifail – Integer Input/Output

6 Error Indicators and Warnings

e04wb preserves all error codes from e04wbf and in addition can return:
An unexpected AD error has been triggered by this routine. Please contact NAG.
See Error Handling in the NAG AD Library Introduction for further information.
The routine was called using a strategy that has not yet been implemented.
See AD Strategies in the NAG AD Library Introduction for further information.
A C++ exception was thrown.
The error message will show the details of the C++ exception text.
Dynamic memory allocation failed for AD.
See Error Handling in the NAG AD Library Introduction for further information.

7 Accuracy

Not applicable.

8 Parallelism and Performance

e04wb is not threaded in any implementation.

9 Further Comments


10 Example

The following examples are variants of the example for e04wbf, modified to demonstrate calling the NAG AD Library.

10.1 Adjoint modes

Language Source File Data Results
Fortran e04wb_a1w_fe.f90 e04wb_a1w_fe.d e04wb_a1w_fe.r
C++ e04wb_a1w_hcppe.cpp e04wb_a1w_hcppe.d e04wb_a1w_hcppe.r

10.2 Tangent modes

Language Source File Data Results
Fortran e04wb_t1w_fe.f90 e04wb_t1w_fe.d e04wb_t1w_fe.r
C++ e04wb_t1w_hcppe.cpp e04wb_t1w_hcppe.d e04wb_t1w_hcppe.r

10.3 Passive mode

Language Source File Data Results
Fortran e04wb_p0w_fe.f90 e04wb_p0w_fe.d e04wb_p0w_fe.r
C++ e04wb_p0w_hcppe.cpp e04wb_p0w_hcppe.d e04wb_p0w_hcppe.r