# NAG CL Interfacee04xxc (nag_opt_init)

Settings help

CL Name Style:

## 1Purpose

e04xxc is the options structure initialization function for Chapter E04. This function or e04xyc must be called before using the options structure.

## 2Specification

 #include
 void e04xxc (Nag_E04_Opt *options)
The function may be called by the names: e04xxc or nag_opt_init.

## 3Description

The optimization functions of Chapter E04 have a number of optional parameters, which are set by means of a structure of type Nag_E04_Opt. Optional parameter values may be assigned to members of an options structure directly in the program text and/or by supplying the optional values in a file which can be read by the function e04xyc.
If optional parameter values are assigned directly in the program text and no use is made of e04xyc, then e04xxc must be called before any assignments are made to the options structure. Initialization is still required even if no assignments are made to the structure before it is passed to the optimization function.
If the file reading function e04xyc is used then this will automatically initialize the options structure if this has not already been done. Any direct assignment to the options structure made after a call to e04xyc must not be preceded by a call to e04xxc otherwise the values set by e04xyc will be lost. Direct assignments to the options structure made before calling e04xyc must, of course, still be preceded by a call to e04xxc.
The purpose of e04xxc is to initialize the options structure members with null values which indicate to the optimization function that the optional parameter that a structure member represents is not to be changed from its default value.

None.

## 5Arguments

1: $\mathbf{options}$Nag_E04_Opt * Output
On exit: the initialized options structure.

None.

Not applicable.