e04 Chapter Contents
e04 Chapter Introduction
NAG C Library Manual

# NAG Library Function Documentnag_opt_nlp_option_set_string (e04wfc)

## 1  Purpose

nag_opt_nlp_option_set_string (e04wfc) may be used to supply individual optional arguments to nag_opt_nlp_solve (e04wdc). The initialization function nag_opt_nlp_init (e04wcc) must have been called before calling nag_opt_nlp_option_set_string (e04wfc).

## 2  Specification

 #include #include
 void nag_opt_nlp_option_set_string (const char *string, Nag_E04State *state, NagError *fail)

## 3  Description

nag_opt_nlp_option_set_string (e04wfc) may be used to supply values for optional arguments to nag_opt_nlp_solve (e04wdc). It is only necessary to call nag_opt_nlp_option_set_string (e04wfc) for those arguments whose values are to be different from their default values. One call to nag_opt_nlp_option_set_string (e04wfc) sets one argument value.
Each optional argument is defined by a single character string, consisting of one or more items. The items associated with a given option must be separated by spaces, or equals signs $\left[=\right]$. Alphabetic characters may be upper or lower case. The string
Print Level = 1
is an example of a string used to set an optional argument. For each option the string contains one or more of the following items:
 – a mandatory keyword; – a phrase that qualifies the keyword; – a number that specifies an Integer or double value. Such numbers may be up to $16$ contiguous characters which can be read using C's d or g formats, terminated by a space if this is not the last item on the line.
For nag_opt_nlp_option_set_string (e04wfc), each user-specified option is not normally printed as it is defined, but this printing may be turned on using the keyword ${\mathbf{List}}$. Thus the statement
e04wfc ("List", &state, &fail);
turns on printing of this and subsequent options. Printing may be turned off again using the keyword ${\mathbf{Nolist}}$.
Optional argument settings are preserved following a call to nag_opt_nlp_solve (e04wdc) and so the keyword ${\mathbf{Defaults}}$ is provided to allow you to reset all the optional arguments to their default values before a subsequent call to nag_opt_nlp_solve (e04wdc).
A complete list of optional arguments, their abbreviations, synonyms and default values is given in Section 11 in nag_opt_nlp_solve (e04wdc).

None.

## 5  Arguments

1:     stringconst char *Input
On entry: a single valid option string (see Section 3 in nag_opt_nlp_option_set_string (e04wfc) and Section 11 in nag_opt_nlp_solve (e04wdc)).
2:     stateNag_E04State *Communication Structure
state contains internal information required for functions in this suite. It must not be modified in any way.
3:     failNagError *Input/Output
The NAG error argument (see Section 3.6 in the Essential Introduction).

## 6  Error Indicators and Warnings

On entry, argument $〈\mathit{\text{value}}〉$ had an illegal value.
NE_E04_OPTION_INVALID
The supplied option is invalid. Check that the keywords are neither ambiguous nor misspelt. The option string is ‘$〈\mathit{\text{value}}〉$’.
NE_E04WCC_NOT_INIT
Initialization function nag_opt_nlp_init (e04wcc) has not been called.
NE_INTERNAL_ERROR
An internal error has occurred in this function. Check the function call and any array sizes. If the call is correct then please contact NAG for assistance.

Not applicable.