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AST_TUNE
-
Set or get an AST global tuning parameter
- Description:
- This function returns the current value of an AST global tuning
parameter, optionally storing a new value for the parameter.
- Invocation:
- RESULT = AST_TUNE( NAME, VALUE, STATUS )
- Arguments:
-
NAME = CHARACTER
(
) (Given)
-
The name of the tuning parameter (case-insensitive).
-
VALUE = INTEGER (Given)
-
The new value for the tuning parameter. If this is AST__TUNULL,
the existing current value will be retained.
-
STATUS = INTEGER (Given and Returned)
-
The global status.
- Returned Value:
-
AST_TUNE = INTEGER
-
be returned if no value has been set for the parameter.
- Notes:
- This routine attempts to execute even if STATUS is set to an
error value
on entry, although no further error report will be
made if it subsequently fails under these circumstances.
- All threads in a process share the same AST tuning parameters
values.
-
Tuning Parameters
:
-
-
ObjectCaching
-
A boolean flag which indicates what should happen
to the memory occupied by an AST Object when the Object is deleted
(i.e. when its reference count falls to zero or it is deleted using
AST_DELETE).
If this is zero, the memory is simply freed using the systems "free"
function. If it is non-zero, the memory is not freed. Instead a
pointer to it is stored in a pool of such pointers, all of which
refer to allocated but currently unused blocks of memory. This allows
AST to speed up subsequent Object creation by re-using previously
allocated memory blocks rather than allocating new memory using the
systems malloc function. The default value for this parameter is
zero. Setting it to a non-zero value will result in Object memory
being cached in future. Setting it back to zero causes any memory
blocks currently in the pool to be freed. Note, this tuning parameter
only controls the caching of memory used to store AST Objects. To
cache other memory blocks allocated by AST, use MemoryCaching.
-
MemoryCaching
-
A boolean flag similar to ObjectCaching except
that it controls caching of all memory blocks of less than 300 bytes
allocated by AST (whether for internal or external use), not just
memory used to store AST Objects.
Next: AST_UINTERP - Perform sub-pixel interpolation on a grid of data
Up: AST Routine Descriptions
Previous: AST_TRANN - Transform N-dimensional coordinates
AST A Library for Handling World Coordinate Systems in Astronomy
Starlink User Note 210
R.F. Warren-Smith & D.S. Berry
24th May 2011
E-mail:ussc@star.rl.ac.uk
Copyright (C) 2009 Science \& Technology Facilities Council