NAG FL Interface
e04ndf
(lsq_lincon_option_file_old)
e04nda (lsq_lincon_option_file)
1
Purpose
To supply optional parameters to
e04ncf/e04nca from an external file. More precisely,
e04ndf must be used to supply optional parameters to
e04ncf and
e04nda must be used to supply optional parameters to
e04nca.
e04nda is a version of
e04ndf that has additional arguments in order to make it safe for use in multithreaded applications (see
Section 5). The initialization routine
e04wbf must have been called before calling
e04nda.
2
Specification
2.1
Specification for e04ndf
Fortran Interface
Integer, Intent (In) |
:: |
ioptns |
Integer, Intent (Out) |
:: |
inform |
|
C++ Header Interface
#include <nag.h> extern "C" {
}
|
2.2
Specification for e04nda
Fortran Interface
Integer, Intent (In) |
:: |
ioptns |
Integer, Intent (Inout) |
:: |
iwsav(610) |
Integer, Intent (Out) |
:: |
inform |
Real (Kind=nag_wp), Intent (Inout) |
:: |
rwsav(475) |
Logical, Intent (Inout) |
:: |
lwsav(120) |
|
C++ Header Interface
#include <nag.h> extern "C" {
}
|
3
Description
e04ndf/e04nda may be used to supply values for optional parameters to
e04ncf/e04nca.
e04ndf/e04nda 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,
of up to
characters,
consisting of one or more items. The items associated with a given option must be separated by spaces, or equals signs
. 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 real value. Such numbers may be up to contiguous characters in Fortran's I, F, E or D 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
For
e04ndf each line of the file is normally printed as it is read, on the current advisory message unit (see
x04abf), but printing may be suppressed using the keyword
Nolist. To suppress printing of
Begin,
Nolist must be the first option supplied as in the file:
Begin
Nolist
Print level = 5
End
Printing will automatically be turned on again after a call to
e04ncf or
e04ndf and may be turned on again at any time using the keyword
List.
For
e04nda printing is turned off by default, but may be turned on at any time using the keyword
List.
Optional parameter settings are preserved following a call to
e04ncf/e04nca and so the keyword
Defaults is provided to allow you to reset all the optional parameters to their default values before a subsequent call to
e04ncf/e04nca.
A complete list of optional parameters, their abbreviations, synonyms and default values is given in
Section 12 in
e04ncf/e04nca.
4
References
None.
5
Arguments
-
1:
– Integer
Input
-
On entry: the unit number of the options file to be read.
Constraint:
.
-
2:
– Integer
Output
-
Note: for e04nda, inform does not occur in this position in the argument list. See the additional arguments described below.
On exit: contains zero if the options file has been successfully read and a
otherwise (see
Section 6).
- Note: the following are additional arguments for specific use with e04nda. Users of e04ndf therefore need not read the remainder of this description.
-
2:
– Logical array
Communication Array
-
3:
– Integer array
Communication Array
-
4:
– Real (Kind=nag_wp) array
Communication Array
-
The arrays
lwsav,
iwsav and
rwsav must not be altered between calls to any of the routines
e04nda,
e04nca,
e04nea or
e04wbf.
-
5:
– Integer
Output
-
Note: see the argument description for
inform above.
6
Error Indicators and Warnings
-
ioptns is not in the range
.
-
Begin was found, but end-of-file was found before End was found.
-
End-of-file was found before Begin was found.
-
One or more lines of the options file is invalid. Check that the keywords are neither ambiguous nor misspelt.
7
Accuracy
Not applicable.
8
Parallelism and Performance
e04ndf/e04nda is not threaded in any implementation.
e04nef/e04nea may also be used to supply optional parameters to
e04ncf/e04nca.
10
Example
This example minimizes the quadratic function
, where
subject to the bounds
and to the general constraints
The initial point, which is feasible, is
and
.
The optimal solution (to five figures) is
and
. Three bound constraints and two general constraints are active at the solution. Note that, although the Hessian matrix is positive semidefinite, the point
is unique.
In this example the options file read by
e04ndf/e04nda is appended to the data file for the program (see
Section 10.2). It would usually be more convenient in practice to keep the data file and the options file separate.
10.1
Program Text
Note: the following programs illustrate the use of e04ndf and e04nda.
10.2
Program Data
10.3
Program Results