Getting started¶

The IDL and Python software tools can be obtained from their GitHub repositories located at github.com/PAHdb/AmesPAHdbIDLSuite and github.com/PAHdb/AmesPAHdbPythonSuite, respectively. Instructions on installing the software tools can be found in the accompanying documentation.

Every interaction with the NASA Ames PAH IR Spectroscopic Database starts out with the creation of a ‘pahdb’-instance, as is illustrated below.

;; Using the OBJ_NEW-function

pahdb = OBJ_NEW('AmesPAHdbIDLSuite')

;; Alternatively, using implicit object creation

pahdb = AmesPAHdbIDLSuite()

from amespahdbpythonsuite.pahdb import Amespahdbpythonsuite
pahdb = amespahdbpythonsuite()

In case the system variable for the default database is not set, or one wishes to load another version or type of database, the ‘Filename’-keyword can be specified.

pahdb = OBJ_NEW('AmesPAHdbIDLSuite', Filename='/path/to/xml-file')

pahdb = Amespahdbpythonsuite(filename='/path/to/xml-file')

By default the parsed database XML-file will be cached for faster subsequent access. However, this behavior can be disabled by setting the ‘Cache’-keyword to false.

pahdb = OBJ_NEW('AmesPAHdbIDLSuite', Cache=0)

pahdb = Amespahdbpythonsuite(cache=False)

When parsing a database XML-file, the software will validate its content against a URL-linked Schema. However, validation can be disabled by setting the ‘Check’-keyword to false. This can be useful when not having an active internet connection.

pahdb = OBJ_NEW('AmesPAHdbIDLSuite', Check=0)

pahdb = Amespahdbpythonsuite(check=False)

Of course, it is possible to combine the different keywords.

pahdb = OBJ_NEW('AmesPAHdbIDLSuite', Filename='path/to/xml-file', $
                             Cache=0, Check=0)

pahdb = Amespahdbpythonsuite(filename='/path/to/xml-file',
                             cache=False, check=False)

Lastly, when finished with the ‘pahdb’-instance it should be destroyed when no garbage collection is available.

OBJ_DESTROY,pahdb

del pahdb