Note: a1w denotes that first order adjoints are computed in working precision; this has the corresponding argument type nagad_a1w_w_rtype. Also available is the t1w (first order tangent linear) mode, the interface of which is implied by replacing a1w by t1w throughout this document. Additionally, the p0w (passive interface, as alternative to the FL interface) mode is available and can be inferred by replacing of active types by the corresponding passive types. The method of codifying AD implementations in the routine name and corresponding argument types is described in the NAG AD Library Introduction.

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## 1Purpose

e04ra_a1w_f is the adjoint version of the primal routine e04raf.

## 2Specification

Fortran Interface
 Subroutine e04ra_a1w_f ( ad_handle, handle, nvar, ifail)
 Integer, Intent (In) :: nvar Integer, Intent (Inout) :: ifail Type (c_ptr), Intent (Inout) :: ad_handle Type (c_ptr), Intent (Out) :: handle
 void e04ra_a1w_f_ ( void *&ad_handle, void *handle, const Integer &nvar, Integer &ifail)
The routine may be called by the names e04ra_a1w_f or nagf_opt_handle_init_a1w. The corresponding t1w and p0w variants of this routine are also available.

## 3Description

e04ra_a1w_f is the adjoint version of the primal routine e04raf.
e04raf initializes a data structure for the NAG optimization modelling suite for problems such as, Linear Programming (LP) , Quadratic Programming (QP) , Nonlinear Programming (NLP) , Least Squares (LSQ) problems, Second-order Cone Programming (SOCP) , linear Semidefinite Programming (SDP) and Semidefinite Programming with Bilinear Matrix Inequalities (BMI-SDP). For further information see Section 3 in the documentation for e04raf.

## 5Arguments

In addition to the arguments present in the interface of the primal routine, e04ra_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/Output
On entry: a handle to the AD configuration data object, as created by x10aa_a1w_f.
2: handle – Type(c_ptr) Output
3: nvar – Integer Input
4: ifail – Integer Input/Output

## 6Error Indicators and Warnings

e04ra_a1w_f preserves all error codes from e04raf and in addition can return:
${\mathbf{ifail}}=-89$
See Section 4.8.2 in the NAG AD Library Introduction for further information.
${\mathbf{ifail}}=-899$
Dynamic memory allocation failed for AD.
See Section 4.8.1 in the NAG AD Library Introduction for further information.

Not applicable.

## 8Parallelism and Performance

e04ra_a1w_f is not threaded in any implementation.