# NAG Library Routine Document

## 1Purpose

e04wcf is used to initialize the routine e04wdf.

## 2Specification

Fortran Interface
 Subroutine e04wcf ( iw, rw,
 Integer, Intent (In) :: leniw, lenrw Integer, Intent (Inout) :: ifail Integer, Intent (Out) :: iw(leniw) Real (Kind=nag_wp), Intent (Out) :: rw(lenrw)
#include nagmk26.h
 void e04wcf_ (Integer iw[], const Integer *leniw, double rw[], const Integer *lenrw, Integer *ifail)

## 3Description

e04wcf initializes the arrays iw and rw for the routine e04wdf.

None.

## 5Arguments

1:     $\mathbf{iw}\left({\mathbf{leniw}}\right)$ – Integer arrayCommunication Array
2:     $\mathbf{leniw}$ – IntegerInput
On entry: the dimension of the array iw as declared in the (sub)program from which e04wcf is called.
Constraint: ${\mathbf{leniw}}\ge 600$, see routine e04wdf.
3:     $\mathbf{rw}\left({\mathbf{lenrw}}\right)$ – Real (Kind=nag_wp) arrayCommunication Array
4:     $\mathbf{lenrw}$ – IntegerInput
On entry: the dimension of the array rw as declared in the (sub)program from which e04wcf is called.
Constraint: ${\mathbf{lenrw}}\ge 600$, see routine e04wdf.
5:     $\mathbf{ifail}$ – 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).

## 6Error Indicators and Warnings

If on entry ${\mathbf{ifail}}=0$ or $-1$, explanatory error messages are output on the current error message unit (as defined by x04aaf).
Errors or warnings detected by the routine:
${\mathbf{ifail}}=1$
One or more of the communication array lengths leniw or lenrw is less than $600$.
${\mathbf{ifail}}=-99$
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.

Not applicable.

## 8Parallelism and Performance

e04wcf is not threaded in any implementation.