NAG FL Interface
e04wlf (nlp2_​option_​double_​get)

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1 Purpose

e04wlf is used to get the value of a real optional parameter. e04wlf can be used before or after calling e04wdf.

2 Specification

Fortran Interface
Subroutine e04wlf ( string, rvalue, iw, rw, ifail)
Integer, Intent (Inout) :: iw(*), ifail
Real (Kind=nag_wp), Intent (Inout) :: rw(*)
Real (Kind=nag_wp), Intent (Out) :: rvalue
Character (*), Intent (In) :: string
C Header Interface
#include <nag.h>
void  e04wlf_ (const char *st, double *rvalue, Integer iw[], double rw[], Integer *ifail, const Charlen length_st)
The routine may be called by the names e04wlf or nagf_opt_nlp2_option_double_get.

3 Description

e04wlf obtains the current value of a real option. For example
Call e04wlf ('LU Factor Tolerance', factol, iw, rw, ifail)
will result in the value of the optional parameter LU Factor Tolerance being output in FACTOL.
A complete list of optional parameters, their abbreviations, synonyms and default values is given in Section 12 in e04wdf.

4 References

None.

5 Arguments

1: string Character(*) Input
On entry: a single valid keyword of a real optional parameter (as described in Section 12 in e04wdf).
2: rvalue Real (Kind=nag_wp) Output
On exit: the real value associated with the keyword in string.
3: iw(*) Integer array Communication Array
Note: the actual argument supplied must be the array iw supplied to the initialization routine e04wcf.
4: rw(*) Real (Kind=nag_wp) array Communication Array
Note: the actual argument supplied must be the array rw supplied to the initialization routine e04wcf.
5: ifail Integer Input/Output
On entry: ifail must be set to 0, −1 or 1 to set behaviour on detection of an error; these values have no effect when no error is detected.
A value of 0 causes the printing of an error message and program execution will be halted; otherwise program execution continues. A value of −1 means that an error message is printed while a value of 1 means that it is not.
If halting is not appropriate, the value −1 or 1 is recommended. If message printing is undesirable, then the value 1 is recommended. Otherwise, the value 0 is recommended. When the value -1 or 1 is used it is essential to test the value of ifail on exit.
On exit: ifail=0 unless the routine detects an error or a warning has been flagged (see Section 6).

6 Error Indicators and Warnings

If on entry 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:
ifail=1
The initialization routine e04wcf has not been called.
ifail=2
The supplied option string is invalid. Check that the keywords are neither ambiguous nor misspelt. The option string is ‘value’.
ifail=-99
An unexpected error has been triggered by this routine. Please contact NAG.
See Section 7 in the Introduction to the NAG Library FL Interface for further information.
ifail=-399
Your licence key may have expired or may not have been installed correctly.
See Section 8 in the Introduction to the NAG Library FL Interface for further information.
ifail=-999
Dynamic memory allocation failed.
See Section 9 in the Introduction to the NAG Library FL Interface for further information.

7 Accuracy

Not applicable.

8 Parallelism and Performance

Background information to multithreading can be found in the Multithreading documentation.
e04wlf is not threaded in any implementation.

9 Further Comments

None.

10 Example

See e04wef.