# NAG CL Interfacee04udc (nlp1_​option_​file)

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## 1Purpose

To supply optional parameters to e04ufc from an external file.

## 2Specification

 #include
 void e04udc (Nag_FileID fileid, Nag_Boolean lwsav[], Integer iwsav[], double rwsav[], NagError *fail)
The function may be called by the names: e04udc, nag_opt_nlp1_option_file or nag_opt_nlp_revcomm_option_set_file.

## 3Description

e04udc may be used to supply values for optional parameters to e04ufc. e04udc reads an external file and each line of the file defines a single optional parameter. It is only necessary to supply values for those arguments whose values are to be different from their default values.
Each optional parameter 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 parameter. 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 $40$ 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.
Blank strings and comments are ignored. A comment begins with an asterisk (*) and all subsequent characters in the string are regarded as part of the comment.
The file containing the options must start with Begin and must finish with End. An example of a valid options file is:
```Begin * Example options file
Print level = 5
End```
Printing of user-supplied options is turned off by default, but may be turned on at any time using the keyword ${\mathbf{List}}$.
Optional parameter settings are preserved following a call to e04ufc and so the keyword ${\mathbf{Defaults}}$ is provided to allow you to reset all the optional parameters to their default values before a subsequent call to e04ufc.
A complete list of optional parameters, their abbreviations, synonyms and default values is given in Section 12 in e04ufc.

None.

## 5Arguments

1: $\mathbf{fileid}$Nag_FileID Input
On entry: the ID of the option file to be read as returned by a call to x04acc.
2: $\mathbf{lwsav}\left[120\right]$Nag_Boolean Communication Array
3: $\mathbf{iwsav}\left[610\right]$Integer Communication Array
4: $\mathbf{rwsav}\left[475\right]$double Communication Array
The arrays lwsav, iwsav and rwsav MUST NOT be altered between calls to any of the functions e04udc, e04uec, e04ufc or e04wbc.
5: $\mathbf{fail}$NagError * Input/Output
The NAG error argument (see Section 7 in the Introduction to the NAG Library CL Interface).

## 6Error Indicators and Warnings

NE_ALLOC_FAIL
Dynamic memory allocation failed.
See Section 3.1.2 in the Introduction to the NAG Library CL Interface for further information.
On entry, argument $⟨\mathit{\text{value}}⟩$ had an illegal value.
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.
See Section 7.5 in the Introduction to the NAG Library CL Interface for further information.
NE_INVALID_OPTION
One or more lines of the options file is invalid. Check that the keywords are neither ambiguous nor misspelt.
NE_MISSING_BEGIN
End-of-file was found before Begin was found.
NE_MISSING_END
Begin was found, but end-of-file was found before End was found.
NE_NO_LICENCE
Your licence key may have expired or may not have been installed correctly.
See Section 8 in the Introduction to the NAG Library CL Interface for further information.
Could not open options file with ${\mathbf{fileid}}=⟨\mathit{\text{value}}⟩$.

Not applicable.

## 8Parallelism and Performance

e04udc is not threaded in any implementation.

e04uec may also be used to supply optional parameters to e04ufc.

## 10Example

This example solves the same problem as the example for e04ufc, but in addition illustrates the use of e04udc and e04uec to set optional parameters for e04ufc.

### 10.1Program Text

Program Text (e04udce.c)

### 10.2Program Data

Program Options (e04udce.opt)
Program Data (e04udce.d)

### 10.3Program Results

Program Results (e04udce.r)