cf.CONSTANTS

cf.CONSTANTS

A dictionary of useful constants.

Whilst the dictionary may be modified directly, it is safer to retrieve and set the values with a function where one is provided. This is due to interdependencies between some values.

Keys :

ATOL : float

The value of absolute tolerance for testing numerically tolerant equality. Retrieved and set with the ATOL function.

CHUNKSIZE : int

The chunk size (in bytes) for data storage and processing. Retrieved and set with the CHUNKSIZE function.

FM_THRESHOLD : float

The minimum amount of memory (in kibibytes) to be kept free for temporary work space. Retrieved and set with the FM_THRESHOLD function.

MINNCFM : int

The number of chunk sizes to be kept free for temporary work space. Retrieved and set with the MINNCFM function.

OF_FRACTION : float

The fraction of the maximum number of concurrently open files which may be used for files containing data arrays. Retrieved and set with the OF_FRACTION function.

RTOL : float

The value of relative tolerance for testing numerically tolerant equality. Retrieved and set with the RTOL function.

TEMPDIR : str

The location to store temporary files. By default, this will be the default directory used by the tempfile module. Retrieved and set with the TEMPDIR function.

Examples

>>> cf.CONSTANTS
{'ATOL': 2.2204460492503131e-16,
 'CHUNKSIZE': 104857600,
 'FM_THRESHOLD': 1024000.0,
 'MINNCFM': 10,
 'OF_FRACTION': 0.5,
 'RTOL': 2.2204460492503131e-16,
 'TEMPDIR': '/tmp'}
>>> cf.TEMPDIR('/home/me/tmp')
>>> cf.CONSTANTS['MINNCFM'] = 15
>>> cf.CHUNKSIZE(1073741824)
>>> cf.CONSTANTS
{'ATOL': 2.2204460492503131e-16,
 'CHUNKSIZE': 1073741824,
 'FM_THRESHOLD': 15728640.0,
 'MINNCFM': 15,
 'OF_FRACTION': 0.5,
 'RTOL': 2.2204460492503131e-16,
 'TEMPDIR': '/home/me/tmp'}