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FAQ

• Why doesn't the code in this guide work with my installation?

  You are probably using a version of the AmesPAHdbIDLSuite dated prior February 14, 2015. Please update to a newer version.

• Does the AmesPAHdbIDLSuite work with GDL?

  The AmesPAHdbIDLSuite might work with GDL, the open source alternative to IDL.

• How does the AmesPAHdbIDLSuite deal with color output?

  The AmesPAHdbIDLSuite 'Plot'-methods create and load a color table containing 15 colors. When outputting to screen, the device will be set into discrete graphics mode. Upon completion, both the color table and the display mode will be restored to their initial settings.

• Where have the C-routines gone?

  The C-code has been removed from the AmesPAHdbIDLSuite for three reasons. First, The NNLS implementation in the suite now makes use of IDL’s LA_LEAST_SQUARES-routine, which is implemented using LAPACK and therefore very fast. Second, it appears that IDL’s READS-routine has seen some significant speed improvements in recent IDL releases such that the CONVERT_ASCII C-implementation has become obsolete. Third and last, making the C-routines compile and reliable across multiple platforms has proven to be difficult.

• I am getting schema validation errors, is this an issue and how can I get rid of them?

  Schema validation errors typically do not cause a problem. The errors you see could be related to the move from www.astrochem.org to www.astrochemistry.org for the base URL, affecting the used XML namespaces. Re-downloading your database XML-file should solve the problem. As a last resort, you can disable schema validation by setting the 'Check'-keyword to 'Check=0' when creating the AmesPAHdbIDLSuite-object.

• I am getting an unsupported protocol in URL error, what can I do?

  With the recent move to using SSL (https) on our domain (www.astrochemistry.org) IDL's XML-parser fails to download the linked schema for checking the structure of the database file. By setting the 'CHECK'-keyword to '0' in the OBJ_NEW-call will mitigate the problem. Note that you might need to manually remove the corrupted cache file.

• I am receiving an invalid multi-byte sequence error, what can I do?

  It has been reported that on older versions of some operating systems IDL's XML-parser is unable to properly handle the utf-8 characters embedded in the database XML-file. One solution is to move to a more modern version of your operation system. Another possible solution is converting the file to use a different encoding with the following command.

  xmllint --encode latin1 --output converted.xml file_with_UTF-8.xml

  Note that characters that cannot be converted are simply removed.