DATAFILE

Datafile class constructor. This is an extension of DATASET.

     A = DATAFILE(DIRECTORY,TYPE,READCMD,P1,P2,P3, ...)
     A = DATAFILE(DIRECTORY,READCMD,P1,P2,P3, ...)

Input
DIRECTORY	Data directory
TYPE	Datafile type (default 'raw')
READCMD	Command (m-file) for reading files in DIRECTORY.  Default: IMREAD
P1,P2,P3	Optional parameters of READCMD

Output
A	Datafile

Description

Datafiles prepare and enable the handling of datasets distributed over  multiple files, i.e. all files of DIRECTORY. Datafiles inherit all  dataset fields. Consequently, most commands defined on datasets also  operate on datafiles with the exception of a number of trainable  mappings. There are five types of datafiles defined (TYPE)

'raw'	Every file is interpreted as a single object in the  dataset. All objects in the same sub-directory of  DIRECTORY receive the name of that sub-directory as class  label. Files may be preprocessed before conversion to  dataset by FILTM. At conversion time they should have the  same size (number of features).
'cell'	All files in DIRECTORY should be mat-files containing just  a single variable being a cell array. Its elements are  interpreted as objects. The file names will be used as  labels during construction. This may be changed by the  user afterwards.
'pre-cooked'	It is expected that READCMD outputs for all files a  dataset with the same label list and the same feature size.
'half-baked'	All files in DIRECTORY should be mat-files,  containing a single dataset. All datasets should have the  same label list and the same feature size.
'mature'	This is a datafile directory constructed by SAVEDATAFILE.  It executes all processing before creation.

For all datafile types holds that execution of mappings (by FILTM or  otherwise and conversion to a dataset (by DATASET) is postponed as long as  possible. Commands are stored inside one of the datafile fields.  Consequently, errors might be detected at a later stage.

The construction by DATAFILE still might be time consuming as for some types  all files have to be checked. For that reason PRTools attempts to save a  mat-file with the DATAFILE definition in DIRECTORY. If it is encountered, it  is loaded avoiding a redefinition.

See also

datafiles, datasets, mappings, filtm, savedatafile, createdatafile,